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WO2009096123A1 - METHOD FOR GROWING AlxGa1-xN SINGLE CRYSTAL - Google Patents

METHOD FOR GROWING AlxGa1-xN SINGLE CRYSTAL Download PDF

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Publication number
WO2009096123A1
WO2009096123A1 PCT/JP2008/073365 JP2008073365W WO2009096123A1 WO 2009096123 A1 WO2009096123 A1 WO 2009096123A1 JP 2008073365 W JP2008073365 W JP 2008073365W WO 2009096123 A1 WO2009096123 A1 WO 2009096123A1
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WO
WIPO (PCT)
Prior art keywords
crystal
aln
seed crystal
single crystal
crucible
Prior art date
Application number
PCT/JP2008/073365
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French (fr)
Japanese (ja)
Inventor
Michimasa Miyanaga
Naho Mizuhara
Keisuke Tanizaki
Tomohiro Kawase
Hideaki Nakahata
Original Assignee
Sumitomo Electric Industries, Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sumitomo Electric Industries, Ltd. filed Critical Sumitomo Electric Industries, Ltd.
Priority to KR1020107015599A priority Critical patent/KR101323868B1/en
Priority to EP08871941.4A priority patent/EP2258890B1/en
Priority to US12/865,397 priority patent/US20100307405A1/en
Priority to CN2008801259815A priority patent/CN101932758A/en
Publication of WO2009096123A1 publication Critical patent/WO2009096123A1/en

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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B23/00—Single-crystal growth by condensing evaporated or sublimed materials
    • C30B23/02—Epitaxial-layer growth
    • C30B23/06—Heating of the deposition chamber, the substrate or the materials to be evaporated
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/40—AIIIBV compounds wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi
    • C30B29/403—AIII-nitrides
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B23/00—Single-crystal growth by condensing evaporated or sublimed materials
    • C30B23/02—Epitaxial-layer growth
    • C30B23/025—Epitaxial-layer growth characterised by the substrate
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/38—Nitrides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/20—Deposition of semiconductor materials on a substrate, e.g. epitaxial growth solid phase epitaxy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02367—Substrates
    • H01L21/0237—Materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02367—Substrates
    • H01L21/0237—Materials
    • H01L21/02373—Group 14 semiconducting materials
    • H01L21/02378—Silicon carbide
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02436—Intermediate layers between substrates and deposited layers
    • H01L21/02439—Materials
    • H01L21/02455—Group 13/15 materials
    • H01L21/02458—Nitrides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H01L21/02538—Group 13/15 materials
    • H01L21/0254—Nitrides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02612—Formation types
    • H01L21/02617—Deposition types
    • H01L21/02631—Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation

Definitions

  • the present invention relates to a large-sized and highly crystalline Al x Ga 1-x N (0 ⁇ x ⁇ 1, hereinafter the same) single crystal growth method preferably used for a semiconductor device substrate or the like.
  • Group III nitride crystals such as Al x Ga 1-x N single crystals are very useful as materials for forming semiconductor devices such as light emitting elements, electronic elements, and semiconductor sensors.
  • a vapor phase method is a viewpoint of obtaining a high-quality single crystal having a small half-value width of a diffraction peak in a rocking curve of X-ray diffraction.
  • Patent Document 1 discloses that an AlN single crystal is grown at a growth rate higher than 0.5 mm / hr by a vapor phase method such as a sublimation method.
  • Patent Document 1 discloses that an AlN single crystal is grown at a growth rate higher than 0.5 mm / hr by a vapor phase method such as a sublimation method.
  • Patent Document 2 describes an AlN bulk single crystal having a crystal diameter of 1 inch (25.4 mm) or more and an impurity content of 450 ppm or less grown on a seed crystal by a sublimation method. Is disclosed.
  • Patent Document 3 discloses an AlN crystal having a length of 10 mm or more, a width of 10 mm or more and a thickness of 300 ⁇ m or more grown by a sublimation method.
  • An Al x Ga 1-x N (0 ⁇ x ⁇ 1) single crystal is generally grown using a sublimation method.
  • the types of crystal growth in the sublimation method include a type in which crystal nuclei are generated without using a base crystal to grow the crystal nuclei (hereinafter also referred to as crystal nucleation growth type), and a type in which crystal growth is performed on the base crystal. (Hereinafter also referred to as a crystal growth type on a base crystal).
  • crystal growth type on a base crystal since it is difficult to obtain a large-diameter Al x Ga 1-x N (0 ⁇ x ⁇ 1) substrate, an Al x Ga 1-x N single crystal to be grown is used.
  • a different base crystal such as a SiC crystal having a different chemical composition from the crystal is used.
  • Al y Ga 1-y N (0 ⁇ y ⁇ 1, hereinafter the same) crystal as a seed crystal as long as it is available as a base crystal.
  • Al y Ga 1-y N seed crystal it depends on the crystal growth method, crystal growth conditions, chemical composition (that is, the type and ratio of elements constituting the crystal), the difference in impurity concentration, etc. Stress is generated between the crystal and the single crystal growing on the seed crystal, and defects such as dislocations, cracks, and warpage are generated in the growing single crystal.
  • An object of the present invention is to solve the above-mentioned problems and to provide a method for growing a large-sized and high-quality Al x Ga 1-x N single crystal.
  • the present invention provides a step of preparing an Al y Ga 1-y N (0 ⁇ y ⁇ 1) seed crystal in which the crystal diameter Dmm and the thickness Tmm satisfy the relationship of T ⁇ 0.003D + 0.15, a step of growing an Al x Ga 1-x N (0 ⁇ x ⁇ 1) single crystal on the main surface of the y Ga 1-y N seed crystal, and a method of growing an Al x Ga 1-x N single crystal. is there.
  • Al y Ga 1-y N seed crystal the crystal by generating a crystal nucleus of Al y Ga 1-y N seed crystal by sublimation It may be a nucleus grown.
  • the Al y Ga 1-y N seed crystal can have a (0001) surface as the main surface.
  • the Al y Ga 1-y N seed crystal can contain at least one element of group IVB elements in a mass ratio of 10 ppm or more.
  • According to the present invention can provide a method for growing a high-quality Al x Ga 1-x N single crystal large.
  • FIG. 1 is a schematic cross-sectional view showing an embodiment of a method for growing an Al x Ga 1-x N single crystal.
  • FIG. 2 is a schematic cross-sectional view showing an embodiment of a method for growing an Al y Ga 1-y N seed crystal.
  • FIG. 3 is a schematic cross-sectional view showing another embodiment of a method for growing an Al y Ga 1-y N seed crystal.
  • FIG. 4 is a graph showing the relationship between the crystal diameter Dmm and the thickness Tmm of the Al y Ga 1-y N seed crystal in Examples and Comparative Examples.
  • the relationship between the crystal diameter D (unit: mm) and the thickness T (unit: mm) is T ⁇ 0.003D + 0.15.
  • Crystal diameter D (mm) and thickness T (mm) and the T ⁇ small satisfies the relation 0.003D + 0.15 thick Al y Ga 1-y Al on the main surface of the N seed crystal x Ga 1-x by growing the N single crystal, Al y Ga 1-y N seed crystal on Al x Ga 1-x N stress generated in the single crystal grown is relaxed, growing Al x Ga 1-x N single Generation of defects such as dislocations, cracks, warpage, etc. in the crystal is suppressed, and a large-sized and high-quality Al x Ga 1-x N single crystal can be obtained. This is particularly effective when the thickness of the Al x Ga 1-x N single crystal to be grown is 1 mm or more.
  • the difference in chemical composition that is,
  • the crystal diameter D (mm) and the thickness T (mm) of the Al y Ga 1-y N seed crystal satisfy the relationship of T ⁇ 0.003D + 0.15 the growth of the Al x Ga 1-x N single crystal is achieved.
  • the stress generated in the Al x Ga 1-x N single crystal grown on the Al y Ga 1-y N seed crystal can be relaxed. From this viewpoint, it is more preferable that the crystal diameter D (mm) and the thickness T (mm) of the Al y Ga 1-y N seed crystal satisfy the relationship of T ⁇ 0.002D + 0.1.
  • the thickness T (mm) of the Al y Ga 1-y N seed crystal is preferably less than 0.25 mm, more preferably less than 0.2 mm, and even more preferably less than 0.15 mm. From the viewpoint of easy handling, the thickness T (mm) of the Al y Ga 1-y N seed crystal is preferably 0.01 mm or more, and more preferably 0.05 mm or more.
  • the step of preparing the Al y Ga 1-y N seed crystal is not particularly limited, and a bulk crystal is grown by using a vapor phase method such as a sublimation method or a liquid phase method such as a solution method (including a flux method). Thereafter, the bulk crystal can be processed so that the crystal diameter D (mm) and the thickness T (mm) satisfy the relationship of T ⁇ 0.003D + 0.15.
  • Al y Ga 1-y N seed defects such as dislocations in the crystal from the viewpoint of reducing the warp and crack, by generating a crystal nucleus of Al y Ga 1-y N seed crystal by sublimation of the crystal nuclei It is preferable to prepare a grown crystal as a seed crystal. Further, Al y Ga 1-y N seeds obtained by growing crystal nuclei from the viewpoint of reducing dislocations in the seed crystal and reducing defects such as dislocations in the grown Al x Ga 1-x N single crystal.
  • the crystal shape preferably satisfies the relationship of D ⁇ 3 with respect to the crystal diameter D (mm) and the thickness T (mm), and more preferably satisfies the relationship of T ⁇ 0.003D + 0.15.
  • the Al x Ga 1-x N single crystal 5 is grown on the main surface 4 m of the Al y Ga 1-y N seed crystal 4 by a sublimation method. A process is provided.
  • stress generated in the Al x Ga 1-x N single crystal can be relieved, Generation of defects such as dislocations, cracks, warpage, and the like is suppressed, and a large, high-quality Al x Ga 1-x N single crystal can be obtained.
  • One type is a type in which a crystal is grown on the main surface of the base crystal (hereinafter also referred to as a crystal growth type on the base crystal) with reference to FIGS.
  • a crystal growth type on the base crystal For example, referring to FIG. 1, Al t Ga 1-t N (0 ⁇ t ⁇ 1, the same shall apply hereinafter) raw material 3 is sublimated and then solidified again to form Al y Ga 1-y N species as a base crystal. An Al x Ga 1-x N (0 ⁇ x ⁇ 1) single crystal 5 is grown on the main surface 4 m of the crystal 4. Further, referring to FIG.
  • Al s Ga 1-s N (0 ⁇ s ⁇ 1, hereinafter the same) raw material 2 is sublimated and then solidified again to form a base crystal such as a SiC crystal or an Al 2 O 3 crystal.
  • An Al y Ga 1-y N seed crystal 4 is grown on 1 m of the main surface 1.
  • the other type is a type in which crystal nuclei are generated without using an underlying crystal and the crystal nuclei are grown (hereinafter also referred to as crystal nucleus growth type) with reference to FIG.
  • crystal nucleus growth type a type in which crystal nuclei are generated without using an underlying crystal and the crystal nuclei are grown
  • a high-frequency heating type vertical sublimation furnace 10 as shown in FIG. 1 is used.
  • a WC crucible 12 having a vent 12c is provided at the center of the reaction vessel 11 in the vertical sublimation furnace 10 so as to ensure ventilation from the inside of the crucible 12 to the outside around the crucible 12.
  • a heating body 13 made of carbon is provided.
  • the crucible 12 includes a crucible body 12q and a crucible lid plate 12p.
  • a high frequency heating coil 14 for heating the heating body 13 is provided in the outer central portion of the reaction vessel 11.
  • N 2 gas inlet 11 a and N 2 gas outlet 11 c for flowing N 2 gas outside the crucible 12 of the reaction vessel 11, and the temperatures of the lower and upper surfaces of the crucible 12.
  • a radiation thermometer 15 is provided for measuring.
  • the step of growing the Al x Ga 1-x N single crystal 5 on the main surface 4m of the Al y Ga 1-y N seed crystal 4 includes:
  • the vertical sublimation furnace 10 is used as follows.
  • the Al t Ga 1-t N raw material 3 is housed in the lower part of the crucible body 12q, and the above-mentioned Al y Ga 1-y N seed crystal 4 is placed on the inner surface of the crucible lid plate 12p with the main surface 4m being Al. arranged so as to face the t Ga 1-t N material 3.
  • the temperature in the crucible 12 is raised by heating the heating element 13 using the high-frequency heating coil 14 while flowing N 2 gas into the reaction vessel 11, and the Al t Ga 1-t N in the crucible 12 is increased.
  • Al x Ga 1-x N is sublimated from the Al t Ga 1-t N raw material 3
  • Al x Ga 1-x N is solidified again on the main surface 4 m of the Al y Ga 1-y N seed crystal 4 to grow an Al x Ga 1-x N single crystal 5.
  • the sublimation temperature and sublimation pressure of Al are different from the sublimation temperature and sublimation pressure of Ga, respectively.
  • the temperature of the crucible 12 on the side of the Al t Ga 1-t N raw material 3 (hereinafter also referred to as sublimation temperature) is about 1600 ° C. to 2300 ° C.
  • the temperature on the Al y Ga 1-y N seed crystal 4 side (hereinafter also referred to as crystal growth temperature) of the crucible 12 is about 10 ° C. to 200 ° C. lower than the temperature (sublimation temperature) on the Al t Ga 1-t N raw material 3 side.
  • the N 2 gas is continuously supplied to the outside of the crucible 12 in the reaction vessel 11 so that the gas partial pressure becomes about 101.3 hPa to 1013 hPa, whereby the Al x Ga 1-x N single crystal 5 Impurities can be reduced.
  • the temperature inside the crucible 12 is made higher than the temperature of the crucible 12 on the side of the Al t Ga 1-t N raw material 3, thereby increasing the impurities inside the crucible 12. Can be discharged through the vent hole 12c, and contamination of impurities into the Al x Ga 1-x N single crystal 5 can be further reduced.
  • the Al y Ga 1-y N seed crystal used in the method for producing an Al x Ga 1-x N single crystal according to the present embodiment generates crystal nuclei of the Al y Ga 1-y N seed crystal by a sublimation method. It is preferable that the crystal nucleus is grown (that is, a crystal nucleus growth type). By such a sublimation method, it is possible to obtain an Al y Ga 1-y N seed crystal having a high quality and a crystal diameter D (mm) and a thickness T (mm) satisfying a relationship of T ⁇ 0.003D + 0.15.
  • the step of growing Al y Ga 1-y N seed crystal 4 by generating crystal nuclei of Al y Ga 1-y N seed crystal 4 by sublimation and growing the crystal nucleus is as follows. For example, it is performed as follows.
  • the Al s Ga 1-s N raw material 2 is accommodated in the lower part of the crucible body 12q, and the crucible lid plate 12p is arranged so as to face the Al s Ga 1-s N raw material 2.
  • the temperature in the crucible 12 is increased by heating the heating body 13 using the high-frequency heating coil 14 while flowing N 2 gas into the reaction vessel 11,
  • the Al s Ga 1 -s N raw material 2 is transformed into Al y Ga 1 -y N.
  • the Al y Ga 1-y N seed crystal 4 is grown.
  • the sublimation temperature and sublimation pressure of Al are different from the sublimation temperature and sublimation pressure of Ga, respectively. Therefore, the relationship between the Al s Ga 1-s N and the composition ratio s of Al in the raw material, Al s Ga 1-s Al sublimes from N material y Ga 1-y N composition ratio y of Al, sublimation temperature Depending on the condition, it has a predetermined relationship at a predetermined sublimation temperature.
  • the temperature (sublimation temperature) of the crucible 12 on the Al s Ga 1-s N raw material 2 side is set to about 1600 ° C. to 2300 ° C.
  • the temperature on the plate 12p side (crystal growth temperature) is set to about 10 ° C. to 200 ° C. lower than the temperature on the Al s Ga 1-s N raw material 2 side (sublimation temperature)
  • high-quality Al y Ga 1-y N species Crystal 4 is obtained.
  • N 2 gas is continuously supplied to the outside of the crucible 12 in the reaction vessel 11 so that the gas partial pressure is about 101.3 hPa to 1013 hPa, whereby the Al y Ga 1-y N seed crystal 4 Impurities can be reduced.
  • the temperature in the other part of the crucible 12 is made higher than the temperature on the Al s Ga 1-s N raw material 2 side of the crucible 12, thereby allowing impurities inside the crucible 12 to pass through the vent 12c. It can be removed, and contamination of impurities into the Al y Ga 1-y N seed crystal 4 can be further reduced.
  • Al y Ga 1-y N seed crystal 4 grown as described above has a polygonal plate shape such as a hexagonal plate shape, and is formed into a polygonal plate shape on crucible lid plate 12p. Are attached in an upright state.
  • Al y Ga 1-y N seed crystal used in the method of manufacturing Al x Ga 1-x N single crystal of the present embodiment Al y Ga 1-y N seed on the main surface of the base crystal by sublimation A crystal grown (that is, a crystal growth type on a base crystal) may be used. Referring to FIG. 3, the step of growing Al y Ga 1-y N seed crystal 4 on main surface 1m of base crystal 1 by the sublimation method is performed, for example, as follows.
  • the Al s Ga 1-s N raw material 2 is housed in the lower part of the crucible body 12q, and crystals such as SiC crystal, Al 2 O 3 crystal, Si crystal, GaN crystal, ZnO crystal are formed on the inner surface of the crucible lid plate 12p.
  • the base crystal 1 having a diameter of Dmm is disposed so that the main surface 1m faces the Al s Ga 1-s N raw material 2.
  • the heating body 13 is heated using the high-frequency heating coil 14 to raise the temperature in the crucible 12, and the Al s Ga 1-s N in the crucible 12 is increased.
  • Al y Ga 1-y N is sublimated from the Al s Ga 1-s N raw material 2, and the main surface 1 m of the base crystal 1
  • Al y Ga 1-y N is solidified again to grow an Al y Ga 1-y N seed crystal 4.
  • the sublimation temperature and sublimation pressure of Al are different from the sublimation temperature and sublimation pressure of Ga, respectively.
  • the temperature of the crucible 12 on the Al s Ga 1-s N raw material 2 side (hereinafter also referred to as sublimation temperature) is set to about 1600 ° C. to 2300 ° C.
  • crystal growth temperature the temperature on the base crystal 1 side (hereinafter also referred to as crystal growth temperature) of the crucible 12 lower by about 10 ° C. to 200 ° C. than the temperature on the Al s Ga 1-s N raw material 2 side (sublimation temperature)
  • N 2 gas is continuously supplied to the outside of the crucible 12 in the reaction vessel 11 so that the gas partial pressure is about 101.3 hPa to 1013 hPa, whereby the Al y Ga 1-y N seed crystal 4 Impurities can be reduced.
  • the temperature inside the crucible 12 is made higher than the temperature of the crucible 12 on the side of the Al s Ga 1-s N raw material 2, so that the impurities inside the crucible 12 are increased. Can be discharged through the vent 12c, and contamination of impurities into the Al y Ga 1-y N seed crystal 4 can be further reduced.
  • the Al y Ga 1-y N seed crystal 4 having the crystal diameter D (mm) and the thickness T 0 (mm) obtained as described above is sliced in a plane parallel to the main surface, and the slice surface is polished.
  • the Al y Ga 1-y N seed crystal 4 satisfying the relationship T ⁇ 0.003D + 0.15 between the crystal diameter D (mm) and the thickness T (mm) (where T 0 > T) is obtained. can get.
  • the Al y Ga 1-y N single crystal 4 used in the Al x Ga 1-x N single crystal growth method of the present embodiment preferably has a (0001) surface as a main surface. Since the Al y Ga 1-y N seed crystal has a (0001) surface as the main surface, a large Al x Ga 1-x N single crystal is grown on the main surface of the Al y Ga 1-y N seed crystal. It becomes easy. From the viewpoint of stably and grow efficiently high quality Al x Ga 1-x N single crystal, Al y Ga 1-y N seed crystal (0001) on the Ga surface, Al x Ga 1-x N single crystal It is preferable to grow.
  • the Al y Ga 1-y N seed crystal 4 used in the Al x Ga 1-x N single crystal growth method of the present embodiment has at least one element of group IVB elements at a mass ratio of 10 ppm or more. It is preferable to contain.
  • the Al y Ga 1-y N seed crystal containing 10 ppm (mass ratio) or more of at least one element of group IVB elements has a (0001) surface as a main surface, and has a hexagonal plate shape or the like. It has a polygonal plate shape and is likely to be a single crystal in which the crystal diameter D (mm) and the thickness T (mm) satisfy the relationship of T ⁇ 0.003D + 0.15.
  • the content of at least one of the group IVB elements is preferably 10 ppm or more, more preferably 50 ppm or more, and even more preferably 100 ppm or more. Further, since an excessive amount of impurities causes defects in the crystal to grow, 5000 ppm or less is preferable and 500 ppm or less is more preferable from the viewpoint of reducing the excessive amount of impurities.
  • the element of the IVB group element means an IVB group element in the long periodic table, and specifically, C (carbon), Si (silicon), Ge (germanium), Sn (tin), Pb (lead) ).
  • Al y Ga 1-y N seed crystal containing 10 ppm (mass ratio) or more of at least one element of group IVB elements there is no particular limitation to grow an Al y Ga 1-y N seed crystal containing 10 ppm (mass ratio) or more of at least one element of group IVB elements.
  • Al s Ga 1- s N raw material 2 with at least one element of IVB group element material (hereinafter, the group IVB element-containing materials) can be grown accommodated in the crucible 12.
  • the content of the IVB group element-containing substance with respect to the entire raw material of the Al s Ga 1-s N raw material 2 and the IVB group element-containing substance is the sum of the IVB group element of the Al s Ga 1-s N and the IVB group element.
  • the content of the IVB group element with respect to is preferably 50 ppm or more, more preferably 500 ppm or more in terms of mass ratio.
  • the temperature (sublimation temperature) on the Al s Ga 1-s N raw material 2 side of the crucible 12 is preferably 1800 ° C. to 2300 ° C. Further, the temperature (crystal growth temperature) on the crucible lid plate 12p side of the crucible 12 is lower by about 10 ° C. to 250 ° C. than the temperature (sublimation temperature) on the Al s Ga 1-s N raw material 2 side, that is, 1550 ° C. to 2290. ° C is preferred.
  • the half width of the diffraction peak in the rocking curve of X-ray diffraction is 150 arcsec or less. Preferably, it is 50 arcsec or less.
  • the dislocation density of the Al y Ga 1-y N seed crystal 4 is preferably 1 ⁇ 10 6 cm ⁇ 2 or less.
  • the method for measuring the dislocation density of the crystal is not particularly limited, and for example, the density of pits (EPD; etch pit density) obtained by etching the surface of the crystal can be measured.
  • Al x Ga 1-x N single crystal On the main surface of a high-quality Al y Ga 1-y N seed crystal having a half-width of a diffraction peak in an X-ray diffraction rocking curve of 150 arcsec or less or a dislocation density of 1 ⁇ 10 6 cm ⁇ 2 or less, An Al x Ga 1-x N single crystal can be grown.
  • Example 1 Growth of AlN seed crystal (Al y Ga 1-y N seed crystal)
  • AlN powder (Al s Ga 1-s N raw material 2) and Si are used as raw materials at the bottom of crucible body 12q made of WC.
  • Powder (IVB group element) was placed.
  • the content rate of Si powder (IVB group element) in the raw material was 300 ppm.
  • an SiC base crystal as the base crystal 1 having a crystal diameter of 40 mm was arranged so that the (0001) Si surface, which is the main surface 1 m, faces the raw material.
  • the temperature in the crucible 12 was increased using the high-frequency heating coil 14 while flowing N 2 gas into the reaction vessel 11.
  • the temperature on the crucible lid plate 12p side of the crucible 12 is set higher than the temperature on the Al s Ga 1-s N raw material 2 side, and the surface of the crucible lid plate 12p is etched during the temperature rise.
  • the impurities released from the crucible 12 during the temperature increase were removed through the vent 12c.
  • the Al s Ga 1-s N raw material 2 side temperature (sublimation temperature) of the crucible 12 is 1700 ° C.
  • the crucible lid plate 12p side temperature (crystal growth temperature) is 1600 ° C.
  • AlN and Si are removed from the raw material. subliming, SiC base crystal 1 (0001) disposed on the inner surface of the crucible cover plate 12p on the Si surface (main surface 1 m), solidifying the AlN again AlN seed crystal (Al y Ga 1-y N A seed crystal 4) was grown.
  • the N 2 gas continues to flow outside the crucible 12 in the reaction vessel 11, and the gas partial pressure outside the crucible 12 in the reaction vessel 11 is increased.
  • the amount of N 2 gas introduced and the amount of N 2 gas discharged were controlled so as to be about 101.3 hPa to 1013 hPa.
  • AlN seed crystal Al y Ga 1-y N seed crystal 4
  • AlN seed crystal Al y Ga 1-y N seed crystal 4
  • a crystal diameter D of 40 mm and a thickness T 0 of 1 mm was grown.
  • AlN seed crystal is sliced in a plane parallel to the main surface, and the slice surface is polished to obtain an AlN seed crystal (Al y Ga 1-y) having a crystal diameter D of 40 mm and a thickness T of 0.21 mm. N seed crystal 4) was obtained.
  • the Si (IVB group element) content in the AlN seed crystal was 80 ppm as measured by SIMS (secondary ion mass spectrometry). When the rocking curve in X-ray diffraction of this AlN seed crystal was measured, the half-width of the diffraction peak was 180 arcsec.
  • AlN single crystal (Al x Ga 1-x N single crystal)
  • AlN powder Al t Ga 1-t N raw material 3
  • AlN seed crystal Al y Ga 1-y N seed crystal 4
  • a crystal diameter D of 40 mm and a thickness T of 0.21 mm on the inner surface of the WC crucible lid plate 12p is 4 m on the main surface.
  • Al surface was arranged to face the AlN powder (Al t Ga 1-t N raw material 3).
  • the temperature in the crucible 12 was raised using the high frequency heating coil 14 while flowing N 2 gas into the reaction vessel 11.
  • Noboru Yutakachu in the crucible 12 the temperature of the crucible cover plate 12p side of the crucible 12 to be higher than the temperature of the Al t Ga 1-t N raw material 3 side, crucible cover plate 12p and AlN seed in warm crystal
  • the surface of (Al y Ga 1-y N seed crystal 4) was cleaned by etching, and impurities released from the crucible 12 during the temperature increase were removed through the vent 12c.
  • the temperature (sublimation temperature) on the Al t Ga 1-t N raw material 3 side of the crucible 12 is 1900 ° C.
  • the temperature (crystal growth temperature) on the Al y Ga 1-y N seed crystal 4 side is 1800 ° C.
  • AlN is sublimated from the raw material
  • AlN is solidified again on the AlN seed crystal (Al y Ga 1-y N seed crystal 4) at the top of the crucible 12 to obtain an AlN single crystal (Al x Ga 1-x N single crystal). 5) was grown.
  • the N 2 gas continues to flow outside the crucible 12 in the reaction vessel 11, and the gas partial pressure outside the crucible 12 in the reaction vessel 11 is reduced.
  • the amount of N 2 gas introduced and the amount of N 2 gas discharged were controlled so as to be about 101.3 hPa to 1013 hPa.
  • AlN single crystal Al x Ga 1-x N single crystal 5
  • Al y Ga 1-y N seed crystal 4 After growing an AlN single crystal (Al x Ga 1-x N single crystal 5) for 30 hours under the above-mentioned crystal growth conditions, cooling to room temperature (25 ° C.) and taking out the crucible lid plate 12p, An AlN single crystal (Al x Ga 1-x N single crystal 5) was grown on the main surface 4m of the crystal (Al y Ga 1-y N seed crystal 4).
  • the AlN single crystal (Al x Ga 1-x N single crystal 5) had a crystal diameter of 40 mm and a thickness of 4 mm.
  • the rocking curve in X-ray diffraction of this AlN single crystal was measured, the half width of the diffraction peak was as small as 220 arcsec.
  • the dislocation density of the AlN single crystal was as low as 5 ⁇ 10 6 cm ⁇ 2 as calculated by EPD (etch pit density) measurement. That is, the AlN single crystal of Example 1 was high quality.
  • EPD etch pit density
  • Example 2 Growth of AlN seed crystal (Al y Ga 1-y N seed crystal)
  • AlN seed crystal having a crystal diameter D of 40 mm and a thickness T 0 of 1 mm was grown.
  • the AlN seed crystal was sliced along a plane parallel to the main surface, and the sliced surface was polished to obtain an AlN seed crystal having a crystal diameter D of 40 mm and a thickness T of 0.24 mm.
  • the Si (IVB group element) content in the AlN seed crystal was 80 ppm. Further, the half width of the diffraction peak in the rocking curve measurement of the X-ray diffraction of this AlN seed crystal was 180 arcsec.
  • AlN single crystal (Al x Ga 1-x N single crystal), the crystal diameter D is the thickness T at 40 mm AlN seed crystal of 0.24mm the (Al y Ga 1-y N seed crystal)
  • An AlN single crystal (Al x Ga 1-x N single crystal 5) was grown in the same manner as in Example 1 except that.
  • the obtained AlN single crystal had a crystal diameter of 40 mm and a thickness of 4 mm.
  • the half-width of the diffraction peak in the X-ray diffraction rocking curve measurement of this AlN single crystal was as small as 230 arcsec.
  • the dislocation density of the AlN single crystal was as low as 6 ⁇ 10 6 cm ⁇ 2 . That is, the AlN single crystal of Example 2 was high quality.
  • Table 1 The results are summarized in Table 1.
  • (Comparative Example 1) Growth of AlN seed crystal (Al y Ga 1-y N seed crystal)
  • the crystal diameter D was 20 mm and the thickness T 0 was the same as in Example 1 except that a SiC base crystal having a crystal diameter of 20 mm was used.
  • a 1 mm AlN seed crystal was grown.
  • the AlN seed crystal was sliced along a plane parallel to the main surface, and the sliced surface was polished to obtain an AlN seed crystal having a crystal diameter D of 20 mm and a thickness T of 0.25 mm.
  • the Si (IVB group element) content in the AlN seed crystal was 80 ppm. Further, the half width of the diffraction peak in the rocking curve measurement of the X-ray diffraction of this AlN seed crystal was 160 arcsec.
  • AlN Single Crystal (Al x Ga 1-x N Single Crystal)
  • AlN seed crystal Al y Ga 1-y N seed crystal
  • An AlN single crystal (Al x Ga 1-x N single crystal 5) was grown in the same manner as in Example 1 except that it was used.
  • the obtained AlN single crystal had a crystal diameter of 20 mm and a thickness of 4 mm.
  • the half-width of the diffraction peak in the X-ray diffraction rocking curve measurement of this AlN single crystal was as large as 350 arcsec.
  • the dislocation density of this AlN single crystal was as high as 5 ⁇ 10 7 cm ⁇ 2 . That is, the AlN single crystal of Example 2 was low quality.
  • Table 1 The results are summarized in Table 1.
  • (Comparative Example 2) Growth of AlN seed crystal (Al y Ga 1-y N seed crystal) Crystal diameter D in the same manner as in Example 1 except that only AlN powder (Al s Ga 1-s N raw material 2) was used as a raw material. An AlN seed crystal having a thickness of 40 mm and a thickness T 0 of 1 mm was grown. The AlN seed crystal was sliced along a plane parallel to the main surface, and the sliced surface was polished to obtain an AlN seed crystal having a crystal diameter D of 40 mm and a thickness T of 0.32 mm. Further, the half width of the diffraction peak in the X-ray diffraction rocking curve measurement of the AlN seed crystal was as large as 280 arcsec.
  • AlN Single Crystal (Al x Ga 1-x N Single Crystal)
  • AlN seed crystal Al y Ga 1-y N seed crystal
  • An AlN single crystal (Al x Ga 1-x N single crystal 5) was grown in the same manner as in Example 1 except that it was used.
  • the obtained AlN single crystal had a crystal diameter of 40 mm and a thickness of 4 mm.
  • the half width of the diffraction peak in the X-ray diffraction rocking curve measurement of this AlN single crystal was as large as 460 arcsec.
  • the dislocation density of the AlN single crystal was as high as 1 ⁇ 10 8 cm ⁇ 2 . That is, the AlN single crystal of Comparative Example 2 was low quality.
  • Table 1 The results are summarized in Table 1.
  • Example 3 Growth of AlN seed crystal (Al y Ga 1-y N seed crystal)
  • AlN powder (Al s Ga 1-s N raw material 2) and Si are used as raw materials at the bottom of crucible body 12q made of WC.
  • Powder (IVB group element) was placed.
  • the content rate of Si powder (IVB group element) in the raw material was 500 ppm.
  • a crucible lid plate 12p made of WC was disposed so as to face the raw material.
  • the temperature in the crucible 12 was raised using the high-frequency heating coil 14 while flowing N 2 gas into the reaction vessel 11.
  • the temperature on the crucible lid plate 12p side of the crucible 12 is set higher than the temperature on the Al s Ga 1-s N raw material 2 side, and the surface of the crucible lid plate 12p is etched during the temperature rise.
  • the impurities released from the crucible 12 during the temperature increase were removed through the vent 12c.
  • the temperature (sublimation temperature) on the Al s Ga 1-s N raw material 2 side of the crucible 12 is 2200 ° C.
  • the temperature (crystal growth temperature) on the crucible lid 12p side is 2150 ° C.
  • AlN and Si are removed from the raw material. sublimating, on top of the crucible cover plate 12p of the crucible 12, it was grown AlN was solidified again AlN seed crystal (Al y Ga 1-y N seed crystal 4).
  • AlN seed crystal Al y Ga 1-y N seed crystal 4
  • the N 2 gas continues to flow outside the crucible 12 in the reaction vessel 11, and the gas partial pressure outside the crucible 12 in the reaction vessel 11 is increased.
  • the amount of N 2 gas introduced and the amount of N 2 gas discharged were controlled so as to be about 101.3 hPa to 1013 hPa.
  • AlN seed crystal Al y Ga 1-y N seed crystal 4
  • one AlN seed crystal had a crystal diameter D of 25 mm and a thickness T of 0.16 mm.
  • the Si (IVB group element) content in the AlN seed crystal was 150 ppm.
  • the full width at half maximum of the diffraction peak in the X-ray diffraction rocking curve measurement of the AlN seed crystal was as small as 70 arcsec. That is, the AlN seed crystal of Example 3 was very high quality.
  • AlN Single Crystal (Al x Ga 1-x N Single Crystal)
  • AlN seed crystal Al y Ga 1-y N seed crystal
  • An AlN single crystal (Al x Ga 1-x N single crystal 5) was grown in the same manner as in Example 1 except that it was used.
  • the obtained AlN single crystal had a crystal diameter of 25 mm and a thickness of 4 mm.
  • the half width of the diffraction peak in the X-ray diffraction rocking curve measurement of this AlN single crystal was very small at 70 arcsec.
  • the dislocation density of the AlN single crystal was as low as 6 ⁇ 10 5 cm ⁇ 2 . That is, the AlN single crystal of Example 3 was very high quality.
  • Table 1 The results are summarized in Table 1.
  • Example 4 Except that AlN seed crystal (Al y Ga 1-y N seed crystal) growth AlN seed crystal (Al y Ga 1-y N seed crystal) growth time was 10 hours, in the same manner as in Example 3, A plurality of AlN seed crystals were grown. Of these AlN seed crystals, one AlN seed crystal had a crystal diameter D of 14 mm and a thickness T of 0.18 mm. The Si (IVB group element) content in the AlN seed crystal was 120 ppm. The half-width of the diffraction peak in the X-ray diffraction rocking curve measurement of this AlN seed crystal was very small at 80 arcsec. That is, the AlN seed crystal of Example 4 was very high quality.
  • AlN single crystal (Al x Ga 1-x N single crystal)
  • AlN seed crystal Al y Ga 1-y N seed crystal
  • An AlN single crystal (Al x Ga 1-x N single crystal 5) was grown in the same manner as in Example 1 except that it was used.
  • the obtained AlN single crystal had a crystal diameter of 14 mm and a thickness of 4 mm.
  • the half width of the diffraction peak in the X-ray diffraction rocking curve measurement of this AlN single crystal was as small as 80 arcsec.
  • the dislocation density of the AlN single crystal was as low as 8 ⁇ 10 5 cm ⁇ 2 . That is, the AlN single crystal of Example 3 was very high quality.
  • Table 1 The results are summarized in Table 1.
  • Example 5 With C (carbon) powder content 400ppm as Group IVB element of growing raw material AlN seed crystal (Al y Ga 1-y N seed crystal), AlN seed crystal (Al y Ga 1-y N seed crystal) A plurality of AlN seed crystals were grown in the same manner as in Example 3 except that the growth time was set to 20 hours. Among these AlN seed crystals, one AlN seed crystal had a crystal diameter D of 22 mm and a thickness T of 0.14 mm. The content of C (IVB group element) in this AlN seed crystal was 120 ppm as measured by SIMS (secondary ion mass spectrometry). The half-width of the diffraction peak in the X-ray diffraction rocking curve measurement of the AlN seed crystal was as extremely small as 25 arcsec. That is, the AlN seed crystal of Example 5 was extremely high quality.
  • AlN Single Crystal (Al x Ga 1-x N Single Crystal)
  • AlN seed crystal Al y Ga 1-y N seed crystal
  • An AlN single crystal (Al x Ga 1 -x) was used in the same manner as in Example 1 except that it was used.
  • N single crystals 5) were grown.
  • the obtained AlN single crystal had a crystal diameter of 22 mm and a thickness of 4 mm.
  • the half width of the diffraction peak in the X-ray diffraction rocking curve measurement of the AlN single crystal was as extremely small as 20 arcsec. Further, the dislocation density of this AlN single crystal was as extremely low as 5 ⁇ 10 4 cm ⁇ 2 . That is, the AlN single crystal of Example 5 was extremely high quality.
  • Table 1 The results are summarized in Table 1.
  • Example 6 With C powder content 600ppm as Group IVB element of growing raw material AlN seed crystal (Al y Ga 1-y N seed crystal), AlN seed crystal (Al y Ga 1-y N seed crystal) growth time A plurality of AlN seed crystals were grown in the same manner as in Example 3 except that the time was 40 hours. Of these AlN seed crystals, one AlN seed crystal had a crystal diameter D of 40 mm and a thickness T of 0.17 mm. The content of C (IVB group element) in this AlN seed crystal was 140 ppm. The half-width of the diffraction peak in the X-ray diffraction rocking curve measurement of the AlN seed crystal was as extremely small as 20 arcsec. That is, the AlN seed crystal of Example 5 was extremely high quality.
  • AlN single crystal (Al x Ga 1-x N single crystal)
  • AlN seed crystal Al y Ga 1-y N seed crystal
  • An AlN single crystal (Al x Ga 1-x N single crystal) was grown in the same manner as in Example 1 except that it was used.
  • the obtained AlN single crystal had a crystal diameter of 40 mm and a thickness of 4 mm.
  • the half-width of the diffraction peak in the X-ray diffraction rocking curve measurement of the AlN single crystal was as extremely small as 15 arcsec. Further, the dislocation density of this AlN single crystal was as extremely low as 9 ⁇ 10 3 cm ⁇ 2 . That is, the AlN single crystal of Example 6 was extremely high quality.
  • Table 1 The results are summarized in Table 1.
  • the relationship between the crystal diameter D (mm) and the thickness T (mm) of the AlN seed crystal (Al y Ga 1-y N seed crystal) is T ⁇ 0.003D + 0.15.
  • the crystal diameter D (mm) and thickness T (mm) of the AlN seed crystal (Al y Ga 1-y N seed crystal) are T ⁇
  • Example 1 (E1) to Example 6 (E6) satisfying the relationship of 0.003D + 0.15, a high-quality AlN single crystal having a small half-value width of a diffraction peak in rocking curve measurement of X-ray diffraction and a low dislocation density (Al x Ga 1-x N single crystal) was obtained.
  • the crystal diameter D (mm) and the thickness T (mm) of the AlN seed crystal (Al y Ga 1-y N seed crystal) satisfy the relationship of 0.002D + 0.1 ⁇ T ⁇ 0.003D + 0.15.
  • example 1 (E1) as compared to ⁇ example (E4), AlN seed crystal (Al y Ga 1-y N seed crystal) crystal diameter D (mm) and thickness T (mm) and the T of ⁇ 0.002D + 0
  • a crystal (Al x Ga 1-x N single crystal) was obtained.
  • Example 1 (E1) to Example (E4) Example 1 (E1) and implementation using an AlN seed crystal (Al y Ga 1-y N seed crystal) grown on a SiC base crystal (base crystal) Compared to Example 2 (E2), Example 3 (E3) and implementation using an AlN seed crystal in which an AlN seed crystal (Al y Ga 1-y N seed crystal) crystal nucleus was generated and grown.
  • Example 4 In Example 4 (E4), a higher quality AlN single crystal (Al x Ga 1-x N single crystal) having a smaller half-width of the diffraction peak and lower dislocation density in the rocking curve measurement of X-ray diffraction was obtained. It was.

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Abstract

Disclosed is a method for growing a large high-quality AlxGa1-xN single crystal. Specifically disclosed is a method for growing an AlxGa1-xN single crystal, which comprises a step of preparing an AlyGa1-yN seed crystal (4) (0 < y ≤ 1) whose crystal diameter D (mm) and thickness T (mm) satisfy the following relation: T < 0.003D + 0.15, and a step of growing an AlxGa1-xN single crystal (5) (0 < x ≤ 1) on the main surface (4m) of the AlyGa1-yN seed crystal (4) by sublimation.

Description

ＡｌxＧａ1-xＮ単結晶の成長方法Method of growing AlxGa1-xN single crystal
  本発明は、半導体デバイスの基板などに好ましく用いられる大型で結晶性のよいＡｌxＧａ1-xＮ（０＜ｘ≦１、以下同じ）単結晶の成長方法に関する。 The present invention relates to a large-sized and highly crystalline Al x Ga 1-x N (0 <x ≦ 1, hereinafter the same) single crystal growth method preferably used for a semiconductor device substrate or the like.
  ＡｌxＧａ1-xＮ単結晶などのＩＩＩ族窒化物結晶は、発光素子、電子素子、半導体センサなどの半導体デバイスを形成するための材料として非常に有用なものである。 Group III nitride crystals such as Al x Ga 1-x N single crystals are very useful as materials for forming semiconductor devices such as light emitting elements, electronic elements, and semiconductor sensors.
  かかるＡｌxＧａ1-xＮ単結晶を作製するための方法としては、気相法、中でも昇華法が、Ｘ線回折のロッキングカーブにおける回折ピークの半値幅が小さい高品質の単結晶を得る観点から、提案されている。たとえば、米国特許第５８５８０８６号明細書（特許文献１）には、昇華法などの気相法により０．５ｍｍ／ｈｒより高い成長速度でＡｌＮ単結晶を成長させることが開示されている。また、米国特許第６２９６９５６号明細書（特許文献２）には、種結晶上に昇華法により成長させた結晶径が１ｉｎｃｈ（２５．４ｍｍ）以上で不純物の含有率が４５０ｐｐｍ以下のＡｌＮバルク単結晶が開示されている。また、米国特許第６００１７４８号明細書（特許文献３）には、昇華法により成長させた長さ１０ｍｍ以上で幅１０ｍｍ以上で厚さ３００μｍ以上のＡｌＮ結晶が開示されている。 As a method for producing such an Al x Ga 1-x N single crystal, a vapor phase method, particularly a sublimation method, is a viewpoint of obtaining a high-quality single crystal having a small half-value width of a diffraction peak in a rocking curve of X-ray diffraction. Has been proposed. For example, US Pat. No. 5,858,086 (Patent Document 1) discloses that an AlN single crystal is grown at a growth rate higher than 0.5 mm / hr by a vapor phase method such as a sublimation method. In addition, US Pat. No. 6,296,956 (Patent Document 2) describes an AlN bulk single crystal having a crystal diameter of 1 inch (25.4 mm) or more and an impurity content of 450 ppm or less grown on a seed crystal by a sublimation method. Is disclosed. In addition, US Pat. No. 6,0017,481 (Patent Document 3) discloses an AlN crystal having a length of 10 mm or more, a width of 10 mm or more and a thickness of 300 μm or more grown by a sublimation method.
  しかし、昇華法で大型（たとえば、直径１ｉｎｃｈ（２５．４ｍｍ）×厚さ２ｍｍ以上、以下同じ）のＡｌxＧａ1-xＮ単結晶を作製しようとすると、結晶成長が不均一となり、転位密度の増大、結晶品質の低下、多結晶の発生などの問題があり、実用的な大きさで転位密度が低く高品質のＡｌxＧａ1-xＮ単結晶を安定して成長させる方法が、未だ提案されていない。
米国特許第５８５８０８６号明細書 米国特許第６２９６９５６号明細書 米国特許第６００１７４８号明細書 However, when an Al x Ga 1-x N single crystal having a large size (for example, a diameter of 1 inch (25.4 mm) × thickness of 2 mm or more, the same applies hereinafter) is attempted by sublimation, the crystal growth becomes non-uniform, and the dislocation density There is still a method for stably growing a high-quality Al x Ga 1-x N single crystal having a practical size and a low dislocation density. Not proposed.
US Pat. No. 5,858,086 US Pat. No. 6,296,956 US Pat. No. 6,0017,481
  ＡｌxＧａ1-xＮ（０＜ｘ≦１）単結晶は、一般に昇華法を用いて成長される。かかる昇華法における結晶成長のタイプには、下地結晶を用いないで結晶核を生成させてこの結晶核を成長させるタイプ（以下、結晶核成長タイプともいう）と、下地結晶上に結晶成長させるタイプ（以下、下地結晶上結晶成長タイプともいう）がある。ここで、下地結晶上結晶成長タイプにおいては、大口径のＡｌxＧａ1-xＮ（０＜ｘ≦１）基板を入手することが困難であるため、成長させるＡｌxＧａ1-xＮ単結晶とは化学組成が異なるＳｉＣ結晶などの異種下地結晶が用いられる。 An Al x Ga 1-x N (0 <x ≦ 1) single crystal is generally grown using a sublimation method. The types of crystal growth in the sublimation method include a type in which crystal nuclei are generated without using a base crystal to grow the crystal nuclei (hereinafter also referred to as crystal nucleation growth type), and a type in which crystal growth is performed on the base crystal. (Hereinafter also referred to as a crystal growth type on a base crystal). Here, in the crystal growth type on the base crystal, since it is difficult to obtain a large-diameter Al x Ga 1-x N (0 <x ≦ 1) substrate, an Al x Ga 1-x N single crystal to be grown is used. A different base crystal such as a SiC crystal having a different chemical composition from the crystal is used.
  異種下地結晶を用いる下地結晶上結晶成長タイプにおいては、比較的大口径化が容易である反面、異種下地結晶とその上に成長させるＡｌxＧａ1-xＮ単結晶と間の格子定数や熱膨張率のミスマッチにより転位などの欠陥が発生するため、通常低品質の結晶しか得られない。一方、結晶核成長タイプにおいて、高品質の結晶が得られやすいが、下地結晶を用いないため、安定して大口径のバルク結晶を得ることが難しく、実用に供し得る大型で高品質の結晶を製造することは一般に困難である。 In the crystal growth type on a base crystal using a different base crystal, it is relatively easy to increase the diameter, but on the other hand, the lattice constant and the heat between the different base crystal and the Al x Ga 1-x N single crystal grown on the base crystal. Since defects such as dislocations occur due to mismatch of expansion coefficients, usually only low-quality crystals can be obtained. On the other hand, in the crystal nucleus growth type, it is easy to obtain high-quality crystals, but since a base crystal is not used, it is difficult to stably obtain large-diameter bulk crystals. It is generally difficult to manufacture.
  このため、下地結晶として入手可能な限り大口径のＡｌyＧａ1-yＮ（０＜ｙ≦１、以下同じ）結晶を種結晶として用いることが望まれる。しかし、かかるＡｌyＧａ1-yＮ種結晶を入手しても、結晶成長法、結晶成長条件、化学組成（すなわち結晶を構成する元素の種類と比率）、不純物濃度の違いなどにより、種結晶と種結晶上に成長する単結晶との間に応力が発生し、成長する単結晶に転位などの欠陥、クラック、反りなどが発生する。 For this reason, it is desirable to use a large-diameter Al y Ga 1-y N (0 <y ≦ 1, hereinafter the same) crystal as a seed crystal as long as it is available as a base crystal. However, even if such an Al y Ga 1-y N seed crystal is obtained, it depends on the crystal growth method, crystal growth conditions, chemical composition (that is, the type and ratio of elements constituting the crystal), the difference in impurity concentration, etc. Stress is generated between the crystal and the single crystal growing on the seed crystal, and defects such as dislocations, cracks, and warpage are generated in the growing single crystal.
  本発明は、上記課題を解決して、大型で高品質のＡｌxＧａ1-xＮ単結晶の成長方法を提供することを目的とする。 An object of the present invention is to solve the above-mentioned problems and to provide a method for growing a large-sized and high-quality Al x Ga 1-x N single crystal.
  本発明は、結晶径Ｄｍｍと厚さＴｍｍとがＴ＜０．００３Ｄ＋０．１５の関係を満たすＡｌyＧａ1-yＮ（０＜ｙ≦１）種結晶を準備する工程と、昇華法によりＡｌyＧａ1-yＮ種結晶の主表面上にＡｌxＧａ1-xＮ（０＜ｘ≦１）単結晶を成長させる工程と、を備えるＡｌxＧａ1-xＮ単結晶の成長方法である。 The present invention provides a step of preparing an Al y Ga 1-y N (0 <y ≦ 1) seed crystal in which the crystal diameter Dmm and the thickness Tmm satisfy the relationship of T <0.003D + 0.15, a step of growing an Al x Ga 1-x N (0 <x ≦ 1) single crystal on the main surface of the y Ga 1-y N seed crystal, and a method of growing an Al x Ga 1-x N single crystal. is there.
  本発明にかかるＡｌxＧａ1-xＮ単結晶の成長方法において、ＡｌyＧａ1-yＮ種結晶は、昇華法によりＡｌyＧａ1-yＮ種結晶の結晶核を生成させてその結晶核を成長させたものであってもよい。また、ＡｌyＧａ1-yＮ種結晶は、主表面として（０００１）表面を有することができる。また、ＡｌyＧａ1-yＮ種結晶は、ＩＶＢ族元素のうちの少なくとも１種類の元素を質量比で１０ｐｐｍ以上含有することができる。 In the growing method of Al x Ga 1-x N single crystal according to the present invention, Al y Ga 1-y N seed crystal, the crystal by generating a crystal nucleus of Al y Ga 1-y N seed crystal by sublimation It may be a nucleus grown. Moreover, the Al y Ga 1-y N seed crystal can have a (0001) surface as the main surface. Further, the Al y Ga 1-y N seed crystal can contain at least one element of group IVB elements in a mass ratio of 10 ppm or more.
  本発明によれば、大型で高品質のＡｌxＧａ1-xＮ単結晶の成長方法を提供することができる。 According to the present invention can provide a method for growing a high-quality Al x Ga 1-x N single crystal large.
図１は、ＡｌxＧａ1-xＮ単結晶の成長方法の一実施形態を示す概略断面図である。FIG. 1 is a schematic cross-sectional view showing an embodiment of a method for growing an Al x Ga 1-x N single crystal. 図２は、ＡｌyＧａ1-yＮ種結晶の成長方法の一実施形態を示す概略断面図である。FIG. 2 is a schematic cross-sectional view showing an embodiment of a method for growing an Al y Ga 1-y N seed crystal. 図３は、ＡｌyＧａ1-yＮ種結晶の成長方法の他の実施形態を示す概略断面図である。FIG. 3 is a schematic cross-sectional view showing another embodiment of a method for growing an Al y Ga 1-y N seed crystal. 図４は、実施例および比較例におけるＡｌyＧａ1-yＮ種結晶の結晶径Ｄｍｍと厚さＴｍｍとの関係を示すグラフである。FIG. 4 is a graph showing the relationship between the crystal diameter Dmm and the thickness Tmm of the Al y Ga 1-y N seed crystal in Examples and Comparative Examples.
符号の説明Explanation of symbols
１  下地結晶
１ｍ，４ｍ  主表面
２  ＡｌsＧａ1-sＮ原料
３  ＡｌtＧａ1-tＮ原料
４  ＡｌyＧａ1-yＮ種結晶
５  ＡｌxＧａ1-xＮ単結晶
１０  昇華炉
１１  反応容器
１１ａ  Ｎ2ガス導入口
１１ｃ  Ｎ2ガス排出口
１２  坩堝
１２ｃ  通気口
１２ｐ  坩堝蓋板
１２ｑ  坩堝本体
１３  加熱体
１４  高周波加熱コイル
１５  放射温度計 1 base crystal 1 m, 4m main surface 2 Al s Ga 1-s N raw material 3 Al t Ga 1-t N material 4 Al y Ga 1-y N seed crystal 5 Al x Ga 1-x N single crystal 10 sublimation furnace 11 Reaction vessel 11a N 2 gas inlet 11c N 2 gas outlet 12 crucible 12c vent 12p crucible lid 12q crucible body 13 heating element 14 high frequency heating coil 15 radiation thermometer
  以下、添付図面を参照しながら本発明の実施形態を詳細に説明する。なお、図面の説明において、同一又は同等の要素には同一符号を用い、重複する説明を省略する。また、図面の寸法比率は、説明のものと必ずしも一致していない。
  図１を参照する。本発明にかかるＡｌxＧａ1-xＮ単結晶の成長方法の一実施形態は、結晶径Ｄ（単位：ｍｍ）と厚さＴ（単位：ｍｍ）とがＴ＜０．００３Ｄ＋０．１５の関係を満たすＡｌyＧａ1-yＮ（０＜ｙ≦１）種結晶４を準備する工程と、昇華法によりＡｌyＧａ1-yＮ種結晶４の主表面４ｍ上にＡｌxＧａ1-xＮ（０＜ｘ≦１）単結晶５を成長させる工程と、を備える。結晶径Ｄ（ｍｍ）と厚さＴ（ｍｍ）とがＴ＜０．００３Ｄ＋０．１５の関係を満たす厚さの小さいＡｌyＧａ1-yＮ種結晶の主表面上にＡｌxＧａ1-xＮ単結晶を成長させることにより、ＡｌyＧａ1-yＮ種結晶上に成長するＡｌxＧａ1-xＮ単結晶中に発生する応力が緩和され、成長するＡｌxＧａ1-xＮ単結晶に転位などの欠陥、クラック、反りなどが発生するのが抑制され、大型で高品質のＡｌxＧａ1-xＮ単結晶が得られる。このことは、成長させるＡｌxＧａ1-xＮ単結晶の厚さが１ｍｍ以上の場合に特に有効である。 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and duplicate descriptions are omitted. Further, the dimensional ratios in the drawings do not necessarily match those described.
Please refer to FIG. In one embodiment of the Al x Ga 1-x N single crystal growth method according to the present invention, the relationship between the crystal diameter D (unit: mm) and the thickness T (unit: mm) is T <0.003D + 0.15. Al y Ga 1-y N (0 <y ≦ 1) seed crystal 4 satisfying the above condition, and Al x Ga 1-x on the main surface 4m of the Al y Ga 1-y N seed crystal 4 by sublimation. Growing N (0 <x ≦ 1) single crystal 5. Crystal diameter D (mm) and thickness T (mm) and the T <small satisfies the relation 0.003D + 0.15 thick Al y Ga 1-y Al on the main surface of the N seed crystal x Ga 1-x by growing the N single crystal, Al y Ga 1-y N seed crystal on Al x Ga 1-x N stress generated in the single crystal grown is relaxed, growing Al x Ga 1-x N single Generation of defects such as dislocations, cracks, warpage, etc. in the crystal is suppressed, and a large-sized and high-quality Al x Ga 1-x N single crystal can be obtained. This is particularly effective when the thickness of the Al x Ga 1-x N single crystal to be grown is 1 mm or more.
  ここで、ＡｌyＧａ1-yＮ種結晶と成長させるＡｌxＧａ1-xＮ単結晶の化学組成は、同じ（すなわちｙ＝ｘ）であっても異なって（すなわちｙ≠ｘ）もよいが、ＡｌxＧａ1-xＮ単結晶の成長の際に結晶中に発生する応力を低減する観点から、化学組成の差（すなわち｜ｙ－ｘ｜）が小さいことが好ましく、化学組成が同じ（すなわちｙ＝ｘ）であることがより好ましい。 Here, the chemical composition of the Al y Ga 1-y N seed crystal and the grown Al x Ga 1-x N single crystal may be the same (ie, y = x) or different (ie, y ≠ x). However, from the viewpoint of reducing the stress generated in the crystal during the growth of the Al x Ga 1-x N single crystal, it is preferable that the difference in chemical composition (that is, | y−x |) is small and the chemical composition is the same. (Ie, y = x) is more preferable.
  図１を参照する。本実施形態のＡｌxＧａ1-xＮ単結晶の成長方法は、結晶径Ｄ（ｍｍ）と厚さＴ（ｍｍ）とがＴ＜０．００３Ｄ＋０．１５の関係を満たすＡｌyＧａ1-yＮ（０＜ｙ≦１）種結晶４を準備する工程を備える。ＡｌyＧａ1-yＮ種結晶の結晶径Ｄ（ｍｍ）と厚さＴ（ｍｍ）とがＴ＜０．００３Ｄ＋０．１５の関係を満たすことにより、ＡｌxＧａ1-xＮ単結晶の成長の際に、ＡｌyＧａ1-yＮ種結晶上に成長するＡｌxＧａ1-xＮ単結晶中に発生する応力の緩和が可能となる。かかる観点から、ＡｌyＧａ1-yＮ種結晶の結晶径Ｄ（ｍｍ）と厚さＴ（ｍｍ）とがＴ＜０．００２Ｄ＋０．１の関係を満たすことがより好ましい。 Please refer to FIG. In the growth method of the Al x Ga 1-x N single crystal according to the present embodiment, Al y Ga 1-y satisfying the relationship T <0.003D + 0.15 between the crystal diameter D (mm) and the thickness T (mm). A step of preparing an N (0 <y ≦ 1) seed crystal 4. When the crystal diameter D (mm) and the thickness T (mm) of the Al y Ga 1-y N seed crystal satisfy the relationship of T <0.003D + 0.15, the growth of the Al x Ga 1-x N single crystal is achieved. In this case, the stress generated in the Al x Ga 1-x N single crystal grown on the Al y Ga 1-y N seed crystal can be relaxed. From this viewpoint, it is more preferable that the crystal diameter D (mm) and the thickness T (mm) of the Al y Ga 1-y N seed crystal satisfy the relationship of T <0.002D + 0.1.
  また、上記の観点から、ＡｌyＧａ1-yＮ種結晶の厚さＴ（ｍｍ）は０．２５ｍｍ未満が好ましく、０．２ｍｍ未満がより好ましく、０．１５ｍｍ未満がさらに好ましい。また、ハンドリングが容易な観点から、ＡｌyＧａ1-yＮ種結晶の厚さＴ（ｍｍ）は、０．０１ｍｍ以上が好ましく、０．０５ｍｍ以上がより好ましい。 Further, from the above viewpoint, the thickness T (mm) of the Al y Ga 1-y N seed crystal is preferably less than 0.25 mm, more preferably less than 0.2 mm, and even more preferably less than 0.15 mm. From the viewpoint of easy handling, the thickness T (mm) of the Al y Ga 1-y N seed crystal is preferably 0.01 mm or more, and more preferably 0.05 mm or more.
  ＡｌyＧａ1-yＮ種結晶を準備する工程には、特に制限はなく、昇華法など気相法、溶液法（フラックス法を含む）などの液相法を用いて、バルク結晶を成長させた後そのバルク結晶を結晶径Ｄ（ｍｍ）と厚さＴ（ｍｍ）とがＴ＜０．００３Ｄ＋０．１５の関係を満たすように加工することができる。 The step of preparing the Al y Ga 1-y N seed crystal is not particularly limited, and a bulk crystal is grown by using a vapor phase method such as a sublimation method or a liquid phase method such as a solution method (including a flux method). Thereafter, the bulk crystal can be processed so that the crystal diameter D (mm) and the thickness T (mm) satisfy the relationship of T <0.003D + 0.15.
  また、ＡｌyＧａ1-yＮ種結晶中の転位などの欠陥、反りおよびクラックを低減する観点から、昇華法によりＡｌyＧａ1-yＮ種結晶の結晶核を生成させてその結晶核を成長させたものを種結晶として準備することが好ましい。さらに、種結晶中の転位を低減して、成長させるＡｌxＧａ1-xＮ単結晶の転位などの欠陥を低減する観点から、結晶核を成長させて得られるＡｌyＧａ1-yＮ種結晶の形状は、結晶径Ｄ（ｍｍ）と厚さＴ（ｍｍ）について、Ｄ≧３の関係を満たすことが好ましく、Ｔ＜０．００３Ｄ＋０．１５の関係を満たすことがより好ましい。 Also, Al y Ga 1-y N seed defects such as dislocations in the crystal, from the viewpoint of reducing the warp and crack, by generating a crystal nucleus of Al y Ga 1-y N seed crystal by sublimation of the crystal nuclei It is preferable to prepare a grown crystal as a seed crystal. Further, Al y Ga 1-y N seeds obtained by growing crystal nuclei from the viewpoint of reducing dislocations in the seed crystal and reducing defects such as dislocations in the grown Al x Ga 1-x N single crystal. The crystal shape preferably satisfies the relationship of D ≧ 3 with respect to the crystal diameter D (mm) and the thickness T (mm), and more preferably satisfies the relationship of T <0.003D + 0.15.
  図１をさらに参照する。本実施形態のＡｌxＧａ1-xＮ単結晶の成長方法は、昇華法によりＡｌyＧａ1-yＮ種結晶４の主表面４ｍ上にＡｌxＧａ1-xＮ単結晶５を成長させる工程を備える。かかるＡｌyＧａ1-yＮ種結晶の主面上にＡｌxＧａ1-xＮ単結晶を成長させることにより、ＡｌxＧａ1-xＮ単結晶中に発生する応力の緩和が可能となり、転位などの欠陥、クラック、反りなどの発生が抑制され、大型で高品質のＡｌxＧａ1-xＮ単結晶が得られる。 Still referring to FIG. In the growth method of the Al x Ga 1-x N single crystal of this embodiment, the Al x Ga 1-x N single crystal 5 is grown on the main surface 4 m of the Al y Ga 1-y N seed crystal 4 by a sublimation method. A process is provided. By growing an Al x Ga 1-x N single crystal on the main surface of the Al y Ga 1-y N seed crystal, stress generated in the Al x Ga 1-x N single crystal can be relieved, Generation of defects such as dislocations, cracks, warpage, and the like is suppressed, and a large, high-quality Al x Ga 1-x N single crystal can be obtained.
  昇華法には、以下の２種類の結晶成長のタイプがある。１つのタイプは、図１および図３を参照して、下地結晶の主表面上に結晶を成長させるタイプ（以下、下地結晶上結晶成長タイプともいう。）である。たとえば、図１を参照して、ＡｌtＧａ1-tＮ（０＜ｔ≦１、以下同じ）原料３を昇華させた後再度固化させて、下地結晶としてのＡｌyＧａ1-yＮ種結晶４の主表面４ｍ上にＡｌxＧａ1-xＮ（０＜ｘ≦１）単結晶５を成長させる。また、図３を参照して、ＡｌsＧａ1-sＮ（０＜ｓ≦１、以下同じ）原料２を昇華させた後再度固化させて、ＳｉＣ結晶、Ａｌ2Ｏ3結晶などの下地結晶１の主表面１ｍ上にＡｌyＧａ1-yＮ種結晶４を成長させる。 There are the following two types of crystal growth in the sublimation method. One type is a type in which a crystal is grown on the main surface of the base crystal (hereinafter also referred to as a crystal growth type on the base crystal) with reference to FIGS. For example, referring to FIG. 1, Al t Ga 1-t N (0 <t ≦ 1, the same shall apply hereinafter) raw material 3 is sublimated and then solidified again to form Al y Ga 1-y N species as a base crystal. An Al x Ga 1-x N (0 <x ≦ 1) single crystal 5 is grown on the main surface 4 m of the crystal 4. Further, referring to FIG. 3, Al s Ga 1-s N (0 <s ≦ 1, hereinafter the same) raw material 2 is sublimated and then solidified again to form a base crystal such as a SiC crystal or an Al 2 O 3 crystal. An Al y Ga 1-y N seed crystal 4 is grown on 1 m of the main surface 1.
  もう一つのタイプは、図２を参照して、下地結晶を用いることなく結晶核を生成させてその結晶核を成長させるタイプ（以下、結晶核成長タイプともいう。）である。たとえば、ＡｌsＧａ1-sＮ原料２を昇華させた後再度固化させてＡｌyＧａ1-yＮ種結晶４の結晶核を生成させてその結晶核を成長させることにより、ＡｌyＧａ1-yＮ種結晶４を成長させる。 The other type is a type in which crystal nuclei are generated without using an underlying crystal and the crystal nuclei are grown (hereinafter also referred to as crystal nucleus growth type) with reference to FIG. For example, by sublimating the Al s Ga 1-s N raw material 2 and then solidifying it again to generate crystal nuclei of the Al y Ga 1-y N seed crystal 4 and growing the crystal nuclei, Al y Ga 1 -y N seed crystal 4 is grown.
  昇華法における結晶成長（下地結晶上結晶成長タイプおよび結晶核成長タイプ）においては、たとえば、図１に示すような高周波加熱方式の縦型の昇華炉１０を用いる。この縦型の昇華炉１０における反応容器１１の中央部には、通気口１２ｃを有するＷＣ製の坩堝１２が設けられ、坩堝１２の周りに坩堝１２の内部から外部への通気を確保するようにカーボン製の加熱体１３が設けられている。坩堝１２は、坩堝本体１２ｑと坩堝蓋板１２ｐにより構成されている。また、反応容器１１の外側中央部には、加熱体１３を加熱するための高周波加熱コイル１４が設けられている。さらに、反応容器１１の端部には、反応容器１１の坩堝１２の外部にＮ2ガスを流すためのＮ2ガス導入口１１ａおよびＮ2ガス排出口１１ｃと、坩堝１２の下面および上面の温度を測定するための放射温度計１５が設けられている。 In crystal growth (crystal growth type and crystal nucleus growth type on the base crystal) in the sublimation method, for example, a high-frequency heating type vertical sublimation furnace 10 as shown in FIG. 1 is used. A WC crucible 12 having a vent 12c is provided at the center of the reaction vessel 11 in the vertical sublimation furnace 10 so as to ensure ventilation from the inside of the crucible 12 to the outside around the crucible 12. A heating body 13 made of carbon is provided. The crucible 12 includes a crucible body 12q and a crucible lid plate 12p. In addition, a high frequency heating coil 14 for heating the heating body 13 is provided in the outer central portion of the reaction vessel 11. Further, at the end of the reaction vessel 11, there are N 2 gas inlet 11 a and N 2 gas outlet 11 c for flowing N 2 gas outside the crucible 12 of the reaction vessel 11, and the temperatures of the lower and upper surfaces of the crucible 12. A radiation thermometer 15 is provided for measuring.
  本実施形態のＡｌxＧａ1-xＮ単結晶の成長方法において、ＡｌyＧａ1-yＮ種結晶４の主表面４ｍ上にＡｌxＧａ1-xＮ単結晶５を成長させる工程は、たとえば、図１を参照して、上記縦型の昇華炉１０を用いて、以下のように行なわれる。 In the growth method of the Al x Ga 1-x N single crystal of the present embodiment, the step of growing the Al x Ga 1-x N single crystal 5 on the main surface 4m of the Al y Ga 1-y N seed crystal 4 includes: For example, referring to FIG. 1, the vertical sublimation furnace 10 is used as follows.
  まず、坩堝本体１２ｑの下部にＡｌtＧａ1-tＮ原料３を収納し、坩堝蓋板１２ｐの内面上に、上記のＡｌyＧａ1-yＮ種結晶４を、その主表面４ｍがＡｌtＧａ1-tＮ原料３に対向するように配置する。次に、反応容器１１内にＮ2ガスを流しながら、高周波加熱コイル１４を用いて加熱体１３を加熱することにより坩堝１２内の温度を上昇させて、坩堝１２のＡｌtＧａ1-tＮ原料３側の温度を、ＡｌyＧａ1-yＮ種結晶４側の温度よりも高く保持することによって、ＡｌtＧａ1-tＮ原料３からＡｌxＧａ1-xＮを昇華させて、ＡｌyＧａ1-yＮ種結晶４の主表面４ｍ上でＡｌxＧａ1-xＮを再度固化させてＡｌxＧａ1-xＮ単結晶５を成長させる。ここで、Ａｌの昇華温度および昇華圧力は、Ｇａの昇華温度および昇華圧力とそれぞれ異なる。このため、ＡｌtＧａ1-tＮ原料のＡｌの組成比ｔと、ＡｌtＧａ1-tＮ原料から昇華するＡｌxＧａ1-xＮのＡｌの組成比ｘとの関係は、昇華温度によって変わるが、所定の昇華温度において所定の関係を有する。 First, the Al t Ga 1-t N raw material 3 is housed in the lower part of the crucible body 12q, and the above-mentioned Al y Ga 1-y N seed crystal 4 is placed on the inner surface of the crucible lid plate 12p with the main surface 4m being Al. arranged so as to face the t Ga 1-t N material 3. Next, the temperature in the crucible 12 is raised by heating the heating element 13 using the high-frequency heating coil 14 while flowing N 2 gas into the reaction vessel 11, and the Al t Ga 1-t N in the crucible 12 is increased. By maintaining the temperature on the raw material 3 side higher than the temperature on the Al y Ga 1-y N seed crystal 4 side, Al x Ga 1-x N is sublimated from the Al t Ga 1-t N raw material 3, Al x Ga 1-x N is solidified again on the main surface 4 m of the Al y Ga 1-y N seed crystal 4 to grow an Al x Ga 1-x N single crystal 5. Here, the sublimation temperature and sublimation pressure of Al are different from the sublimation temperature and sublimation pressure of Ga, respectively. Therefore, the relationship between the Al t Ga 1-t N composition ratio and t of Al raw material, Al t Ga 1-t Al sublimes from N material x Ga 1-x N of the Al composition ratio x, the sublimation temperature Depending on the condition, it has a predetermined relationship at a predetermined sublimation temperature.
  ここで、ＡｌxＧａ1-xＮ単結晶５の成長中は、坩堝１２のＡｌtＧａ1-tＮ原料３側の温度（以下、昇華温度ともいう）は１６００℃～２３００℃程度とし、坩堝１２のＡｌyＧａ1-yＮ種結晶４側の温度（以下、結晶成長温度ともいう）をＡｌtＧａ1-tＮ原料３側の温度（昇華温度）より１０℃～２００℃程度低くすることにより、高品質のＡｌxＧａ1-xＮ単結晶５が得られる。また、結晶成長中も反応容器１１内の坩堝１２の外側にＮ2ガスを、ガス分圧が１０１．３ｈＰａ～１０１３ｈＰａ程度になるように流し続けることにより、ＡｌxＧａ1-xＮ単結晶５への不純物の混入を低減することができる。 Here, during the growth of the Al x Ga 1-x N single crystal 5, the temperature of the crucible 12 on the side of the Al t Ga 1-t N raw material 3 (hereinafter also referred to as sublimation temperature) is about 1600 ° C. to 2300 ° C., The temperature on the Al y Ga 1-y N seed crystal 4 side (hereinafter also referred to as crystal growth temperature) of the crucible 12 is about 10 ° C. to 200 ° C. lower than the temperature (sublimation temperature) on the Al t Ga 1-t N raw material 3 side. As a result, a high quality Al x Ga 1-x N single crystal 5 is obtained. Further, during the crystal growth, the N 2 gas is continuously supplied to the outside of the crucible 12 in the reaction vessel 11 so that the gas partial pressure becomes about 101.3 hPa to 1013 hPa, whereby the Al x Ga 1-x N single crystal 5 Impurities can be reduced.
  なお、坩堝１２内部の昇温中は、坩堝１２のＡｌtＧａ1-tＮ原料３側の温度よりも、坩堝１２内におけるそれ以外の部分の温度を高くすることにより、坩堝１２内部の不純物を通気口１２ｃを通じて排出することができ、ＡｌxＧａ1-xＮ単結晶５への不純物の混入をより低減することができる。 During the temperature rise inside the crucible 12, the temperature inside the crucible 12 is made higher than the temperature of the crucible 12 on the side of the Al t Ga 1-t N raw material 3, thereby increasing the impurities inside the crucible 12. Can be discharged through the vent hole 12c, and contamination of impurities into the Al x Ga 1-x N single crystal 5 can be further reduced.
  本実施形態のＡｌxＧａ1-xＮ単結晶の製造方法において用いられるＡｌyＧａ1-yＮ種結晶は、昇華法によりＡｌyＧａ1-yＮ種結晶の結晶核を生成させてその結晶核を成長させたもの（すなわち、結晶核成長タイプ）であることが好ましい。かかる昇華法により、高品質で結晶径Ｄ（ｍｍ）と厚さＴ（ｍｍ）とがＴ＜０．００３Ｄ＋０．１５の関係を満たすＡｌyＧａ1-yＮ種結晶を得ることができる。 The Al y Ga 1-y N seed crystal used in the method for producing an Al x Ga 1-x N single crystal according to the present embodiment generates crystal nuclei of the Al y Ga 1-y N seed crystal by a sublimation method. It is preferable that the crystal nucleus is grown (that is, a crystal nucleus growth type). By such a sublimation method, it is possible to obtain an Al y Ga 1-y N seed crystal having a high quality and a crystal diameter D (mm) and a thickness T (mm) satisfying a relationship of T <0.003D + 0.15.
  図２を参照して、昇華法によりＡｌyＧａ1-yＮ種結晶４の結晶核を生成させてその結晶核を成長させることによりＡｌyＧａ1-yＮ種結晶４を成長させる工程は、たとえば、以下のように行なわれる。 Referring to FIG. 2, the step of growing Al y Ga 1-y N seed crystal 4 by generating crystal nuclei of Al y Ga 1-y N seed crystal 4 by sublimation and growing the crystal nucleus is as follows. For example, it is performed as follows.
  まず、坩堝本体１２ｑの下部にＡｌsＧａ1-sＮ原料２を収納して、ＡｌsＧａ1-sＮ原料２に対向するように坩堝蓋板１２ｐを配置する。次に、図１および図２を参照して、反応容器１１内にＮ2ガスを流しながら、高周波加熱コイル１４を用いて加熱体１３を加熱することにより坩堝１２内の温度を上昇させて、坩堝１２のＡｌsＧａ1-sＮ原料２側の温度を、坩堝蓋板１２ｐ側の温度よりも高く保持することによって、ＡｌsＧａ1-sＮ原料２からＡｌyＧａ1-yＮを昇華させて、坩堝蓋板１２ｐ上で、ＡｌyＧａ1-yＮを再度固化させて、ＡｌyＧａ1-yＮ種結晶４の結晶核を生成させてその結晶核を成長させることにより、ＡｌyＧａ1-yＮ種結晶４を成長させる。ここで、Ａｌの昇華温度および昇華圧力は、Ｇａの昇華温度および昇華圧力とそれぞれ異なる。このため、ＡｌsＧａ1-sＮ原料のＡｌの組成比ｓと、ＡｌsＧａ1-sＮ原料から昇華するＡｌyＧａ1-yＮのＡｌの組成比ｙとの関係は、昇華温度によって変わるが、所定の昇華温度において所定の関係を有する。 First, the Al s Ga 1-s N raw material 2 is accommodated in the lower part of the crucible body 12q, and the crucible lid plate 12p is arranged so as to face the Al s Ga 1-s N raw material 2. Next, referring to FIG. 1 and FIG. 2, the temperature in the crucible 12 is increased by heating the heating body 13 using the high-frequency heating coil 14 while flowing N 2 gas into the reaction vessel 11, By maintaining the temperature of the Al s Ga 1 -s N raw material 2 side of the crucible 12 higher than the temperature of the crucible lid plate 12 p side, the Al s Ga 1 -s N raw material 2 is transformed into Al y Ga 1 -y N. By sublimating and re-solidifying Al y Ga 1-y N on the crucible lid plate 12p, generating crystal nuclei of the Al y Ga 1-y N seed crystal 4 and growing the crystal nuclei, The Al y Ga 1-y N seed crystal 4 is grown. Here, the sublimation temperature and sublimation pressure of Al are different from the sublimation temperature and sublimation pressure of Ga, respectively. Therefore, the relationship between the Al s Ga 1-s N and the composition ratio s of Al in the raw material, Al s Ga 1-s Al sublimes from N material y Ga 1-y N composition ratio y of Al, sublimation temperature Depending on the condition, it has a predetermined relationship at a predetermined sublimation temperature.
  ここで、ＡｌyＧａ1-yＮ種結晶の成長中は、坩堝１２のＡｌsＧａ1-sＮ原料２側の温度（昇華温度）は１６００℃～２３００℃程度とし、坩堝１２の坩堝蓋板１２ｐ側の温度（結晶成長温度）をＡｌsＧａ1-sＮ原料２側の温度（昇華温度）より１０℃～２００℃程度低くすることにより、高品質のＡｌyＧａ1-yＮ種結晶４が得られる。また、結晶成長中も反応容器１１内の坩堝１２の外側にＮ2ガスを、ガス分圧が１０１．３ｈＰａ～１０１３ｈＰａ程度になるように流し続けることにより、ＡｌyＧａ1-yＮ種結晶４への不純物の混入を低減することができる。 Here, during the growth of the Al y Ga 1-y N seed crystal, the temperature (sublimation temperature) of the crucible 12 on the Al s Ga 1-s N raw material 2 side is set to about 1600 ° C. to 2300 ° C. By making the temperature on the plate 12p side (crystal growth temperature) about 10 ° C. to 200 ° C. lower than the temperature on the Al s Ga 1-s N raw material 2 side (sublimation temperature), high-quality Al y Ga 1-y N species Crystal 4 is obtained. Further, during crystal growth, N 2 gas is continuously supplied to the outside of the crucible 12 in the reaction vessel 11 so that the gas partial pressure is about 101.3 hPa to 1013 hPa, whereby the Al y Ga 1-y N seed crystal 4 Impurities can be reduced.
  なお、坩堝１２内部の昇温中は、坩堝１２のＡｌsＧａ1-sＮ原料２側の温度よりもそれ以外の部分の温度を高くすることにより、坩堝１２内部の不純物を通気口１２ｃを通じて除去することができ、ＡｌyＧａ1-yＮ種結晶４への不純物の混入をより低減することができる。 During the temperature rise inside the crucible 12, the temperature in the other part of the crucible 12 is made higher than the temperature on the Al s Ga 1-s N raw material 2 side of the crucible 12, thereby allowing impurities inside the crucible 12 to pass through the vent 12c. It can be removed, and contamination of impurities into the Al y Ga 1-y N seed crystal 4 can be further reduced.
  図２を参照して、上記のようにして成長されたＡｌyＧａ1-yＮ種結晶４は、六角平板状などの多角平板状の形状を有し、坩堝蓋板１２ｐ上に多角平板状の結晶が起立した状態で付着している。 Referring to FIG. 2, Al y Ga 1-y N seed crystal 4 grown as described above has a polygonal plate shape such as a hexagonal plate shape, and is formed into a polygonal plate shape on crucible lid plate 12p. Are attached in an upright state.
  また、本実施形態のＡｌxＧａ1-xＮ単結晶の製造方法において用いられるＡｌyＧａ1-yＮ種結晶は、昇華法により下地結晶の主表面上にＡｌyＧａ1-yＮ種結晶を成長させたもの（すなわち、下地結晶上結晶成長タイプ）であってもよい。図３を参照して、昇華法により下地結晶１の主表面１ｍ上にＡｌyＧａ1-yＮ種結晶４を成長させる工程は、たとえば、以下のように行なわれる。 Also, Al y Ga 1-y N seed crystal used in the method of manufacturing Al x Ga 1-x N single crystal of the present embodiment, Al y Ga 1-y N seed on the main surface of the base crystal by sublimation A crystal grown (that is, a crystal growth type on a base crystal) may be used. Referring to FIG. 3, the step of growing Al y Ga 1-y N seed crystal 4 on main surface 1m of base crystal 1 by the sublimation method is performed, for example, as follows.
  まず、坩堝本体１２ｑの下部にＡｌsＧａ1-sＮ原料２を収納し、坩堝蓋板１２ｐの内面上に、ＳｉＣ結晶、Ａｌ2Ｏ3結晶、Ｓｉ結晶、ＧａＮ結晶、ＺｎＯ結晶などの結晶径Ｄｍｍの下地結晶１を、その主表面１ｍがＡｌsＧａ1-sＮ原料２に対向するように配置する。 First, the Al s Ga 1-s N raw material 2 is housed in the lower part of the crucible body 12q, and crystals such as SiC crystal, Al 2 O 3 crystal, Si crystal, GaN crystal, ZnO crystal are formed on the inner surface of the crucible lid plate 12p. The base crystal 1 having a diameter of Dmm is disposed so that the main surface 1m faces the Al s Ga 1-s N raw material 2.
  次に、反応容器１１内にＮ2ガスを流しながら、高周波加熱コイル１４を用いて加熱体１３を加熱することにより坩堝１２内の温度を上昇させて、坩堝１２のＡｌsＧａ1-sＮ原料２側の温度を、下地結晶１側の温度よりも高く保持することによって、ＡｌsＧａ1-sＮ原料２からＡｌyＧａ1-yＮを昇華させて、下地結晶１の主表面１ｍ上でＡｌyＧａ1-yＮを再度固化させてＡｌyＧａ1-yＮ種結晶４を成長させる。ここで、Ａｌの昇華温度および昇華圧力は、Ｇａの昇華温度および昇華圧力とそれぞれ異なる。このため、ＡｌsＧａ1-sＮ原料のＡｌの組成比ｓと、ＡｌsＧａ1-sＮ原料から昇華するＡｌyＧａ1-yＮのＡｌの組成比ｙとの関係は、昇華温度によって変わるが、所定の昇華温度において所定の関係を有する。 Next, while flowing the N 2 gas into the reaction vessel 11, the heating body 13 is heated using the high-frequency heating coil 14 to raise the temperature in the crucible 12, and the Al s Ga 1-s N in the crucible 12 is increased. By maintaining the temperature on the raw material 2 side higher than the temperature on the base crystal 1 side, Al y Ga 1-y N is sublimated from the Al s Ga 1-s N raw material 2, and the main surface 1 m of the base crystal 1 Then, Al y Ga 1-y N is solidified again to grow an Al y Ga 1-y N seed crystal 4. Here, the sublimation temperature and sublimation pressure of Al are different from the sublimation temperature and sublimation pressure of Ga, respectively. Therefore, the relationship between the Al s Ga 1-s N and the composition ratio s of Al in the raw material, Al s Ga 1-s Al sublimes from N material y Ga 1-y N composition ratio y of Al, sublimation temperature Depending on the condition, it has a predetermined relationship at a predetermined sublimation temperature.
  ここで、ＡｌyＧａ1-yＮ種結晶４の成長中は、坩堝１２のＡｌsＧａ1-sＮ原料２側の温度（以下、昇華温度ともいう。）は１６００℃～２３００℃程度とし、坩堝１２の下地結晶１側の温度（以下、結晶成長温度ともいう）をＡｌsＧａ1-sＮ原料２側の温度（昇華温度）より１０℃～２００℃程度低くすることにより、高品質の結晶径Ｄ（ｍｍ）で厚さＴ0（ｍｍ）のＡｌyＧａ1-yＮ種結晶４が得られる。また、結晶成長中も反応容器１１内の坩堝１２の外側にＮ2ガスを、ガス分圧が１０１．３ｈＰａ～１０１３ｈＰａ程度になるように流し続けることにより、ＡｌyＧａ1-yＮ種結晶４への不純物の混入を低減することができる。 Here, during the growth of the Al y Ga 1-y N seed crystal 4, the temperature of the crucible 12 on the Al s Ga 1-s N raw material 2 side (hereinafter also referred to as sublimation temperature) is set to about 1600 ° C. to 2300 ° C. By making the temperature on the base crystal 1 side (hereinafter also referred to as crystal growth temperature) of the crucible 12 lower by about 10 ° C. to 200 ° C. than the temperature on the Al s Ga 1-s N raw material 2 side (sublimation temperature), high quality An Al y Ga 1-y N seed crystal 4 having a crystal diameter D (mm) and a thickness T 0 (mm) is obtained. Further, during crystal growth, N 2 gas is continuously supplied to the outside of the crucible 12 in the reaction vessel 11 so that the gas partial pressure is about 101.3 hPa to 1013 hPa, whereby the Al y Ga 1-y N seed crystal 4 Impurities can be reduced.
  なお、坩堝１２内部の昇温中は、坩堝１２のＡｌsＧａ1-sＮ原料２側の温度よりも、坩堝１２内におけるそれ以外の部分の温度を高くすることにより、坩堝１２内部の不純物を通気口１２ｃを通じて排出することができ、ＡｌyＧａ1-yＮ種結晶４への不純物の混入をより低減することができる。 During the temperature rise inside the crucible 12, the temperature inside the crucible 12 is made higher than the temperature of the crucible 12 on the side of the Al s Ga 1-s N raw material 2, so that the impurities inside the crucible 12 are increased. Can be discharged through the vent 12c, and contamination of impurities into the Al y Ga 1-y N seed crystal 4 can be further reduced.
  上記のようにして得られた結晶径Ｄ（ｍｍ）で厚さＴ0（ｍｍ）のＡｌyＧａ1-yＮ種結晶４をその主表面に平行な面でスライスして、スライス面を研磨することにより、結晶径Ｄ（ｍｍ）と厚さＴ（ｍｍ）（ここで、Ｔ0＞Ｔ）とがＴ＜０．００３Ｄ＋０．１５の関係を満たすＡｌyＧａ1-yＮ種結晶４が得られる。 The Al y Ga 1-y N seed crystal 4 having the crystal diameter D (mm) and the thickness T 0 (mm) obtained as described above is sliced in a plane parallel to the main surface, and the slice surface is polished. As a result, the Al y Ga 1-y N seed crystal 4 satisfying the relationship T <0.003D + 0.15 between the crystal diameter D (mm) and the thickness T (mm) (where T 0 > T) is obtained. can get.
  ここで、本実施形態のＡｌxＧａ1-xＮ単結晶の成長方法に用いられるＡｌyＧａ1-yＮ単結晶４は、主表面として（０００１）表面を有することが好ましい。ＡｌyＧａ1-yＮ種結晶が主表面として（０００１）表面を有することより、ＡｌyＧａ1-yＮ種結晶の主面上に大型のＡｌxＧａ1-xＮ単結晶を成長させることが容易となる。高品質のＡｌxＧａ1-xＮ単結晶を安定にかつ効率よく成長させる観点から、ＡｌyＧａ1-yＮ種結晶の（０００１）Ｇａ表面上に、ＡｌxＧａ1-xＮ単結晶を成長させることが好ましい。 Here, the Al y Ga 1-y N single crystal 4 used in the Al x Ga 1-x N single crystal growth method of the present embodiment preferably has a (0001) surface as a main surface. Since the Al y Ga 1-y N seed crystal has a (0001) surface as the main surface, a large Al x Ga 1-x N single crystal is grown on the main surface of the Al y Ga 1-y N seed crystal. It becomes easy. From the viewpoint of stably and grow efficiently high quality Al x Ga 1-x N single crystal, Al y Ga 1-y N seed crystal (0001) on the Ga surface, Al x Ga 1-x N single crystal It is preferable to grow.
  また、本実施形態のＡｌxＧａ1-xＮ単結晶の成長方法に用いられるＡｌyＧａ1-yＮ種結晶４は、ＩＶＢ族元素のうちの少なくとも１種類の元素を質量比で１０ｐｐｍ以上含有することが好ましい。ここで、ＩＶＢ族元素のうちの少なくとも１種類の元素を１０ｐｐｍ（質量比）以上含有するＡｌyＧａ1-yＮ種結晶は、主表面として（０００１）表面を有し、六角平板状などの多角平板状の形状を有し、結晶径Ｄ（ｍｍ）と厚さＴ（ｍｍ）とがＴ＜０．００３Ｄ＋０．１５の関係を満たす単結晶となりやすい。かかる観点から、ＩＶＢ族元素のうちの少なくとも１種類の元素の含有率は、１０ｐｐｍ以上が好ましく、５０ｐｐｍ以上がより好ましく、１００ｐｐｍ以上がさらに好ましい。また、過剰な量の不純物は結晶中の欠陥を増殖させるため、過剰な量の不純物を低減する観点から、５０００ｐｐｍ以下が好ましく、５００ｐｐｍ以下がより好ましい。ここで、ＩＶＢ族元素の元素とは、長周期律表におけるＩＶＢ族元素をいい、具体的には、Ｃ（炭素）、Ｓｉ（ケイ素）、Ｇｅ（ゲルマニウム）、Ｓｎ（スズ）、Ｐｂ（鉛）をいう。 Further, the Al y Ga 1-y N seed crystal 4 used in the Al x Ga 1-x N single crystal growth method of the present embodiment has at least one element of group IVB elements at a mass ratio of 10 ppm or more. It is preferable to contain. Here, the Al y Ga 1-y N seed crystal containing 10 ppm (mass ratio) or more of at least one element of group IVB elements has a (0001) surface as a main surface, and has a hexagonal plate shape or the like. It has a polygonal plate shape and is likely to be a single crystal in which the crystal diameter D (mm) and the thickness T (mm) satisfy the relationship of T <0.003D + 0.15. From this point of view, the content of at least one of the group IVB elements is preferably 10 ppm or more, more preferably 50 ppm or more, and even more preferably 100 ppm or more. Further, since an excessive amount of impurities causes defects in the crystal to grow, 5000 ppm or less is preferable and 500 ppm or less is more preferable from the viewpoint of reducing the excessive amount of impurities. Here, the element of the IVB group element means an IVB group element in the long periodic table, and specifically, C (carbon), Si (silicon), Ge (germanium), Sn (tin), Pb (lead) ).
  ここで、ＩＶＢ族元素のうちの少なくとも１種類の元素を１０ｐｐｍ（質量比）以上含有するＡｌyＧａ1-yＮ種結晶を成長させるため、特に制限はないが、たとえば、ＡｌsＧａ1-sＮ原料２とともにＩＶＢ族元素のうちの少なくとも１種類の元素を含む物質（以下、ＩＶＢ族元素含有物質）を坩堝１２に収納して成長させることができる。ここで、ＡｌsＧａ1-sＮ原料２およびＩＶＢ族元素含有物質の全体の原料に対するＩＶＢ族元素含有物質の含有量は、ＩＶＢ族元素がＡｌsＧａ1-sＮおよびＩＶＢ族元素の和に対するＩＶＢ族元素の含有率が、質量比で、好ましくは５０ｐｐｍ以上、より好ましくは５００ｐｐｍ以上となるようにする。 Here, there is no particular limitation to grow an Al y Ga 1-y N seed crystal containing 10 ppm (mass ratio) or more of at least one element of group IVB elements. For example, Al s Ga 1- s N raw material 2 with at least one element of IVB group element material (hereinafter, the group IVB element-containing materials) can be grown accommodated in the crucible 12. Here, the content of the IVB group element-containing substance with respect to the entire raw material of the Al s Ga 1-s N raw material 2 and the IVB group element-containing substance is the sum of the IVB group element of the Al s Ga 1-s N and the IVB group element. The content of the IVB group element with respect to is preferably 50 ppm or more, more preferably 500 ppm or more in terms of mass ratio.
  また、ＡｌyＧａ1-yＮ種結晶の成長中において、坩堝１２のＡｌsＧａ1-sＮ原料２側の温度（昇華温度）は１８００℃～２３００℃が好ましい。また、坩堝１２の坩堝蓋板１２ｐ側の温度（結晶成長温度）は、ＡｌsＧａ1-sＮ原料２側の温度（昇華温度）より１０℃～２５０℃程度低く、すなわち、１５５０℃～２２９０℃が好ましい。 Further, during the growth of the Al y Ga 1-y N seed crystal, the temperature (sublimation temperature) on the Al s Ga 1-s N raw material 2 side of the crucible 12 is preferably 1800 ° C. to 2300 ° C. Further, the temperature (crystal growth temperature) on the crucible lid plate 12p side of the crucible 12 is lower by about 10 ° C. to 250 ° C. than the temperature (sublimation temperature) on the Al s Ga 1-s N raw material 2 side, that is, 1550 ° C. to 2290. ° C is preferred.
  また、本実施形態のＡｌxＧａ1-xＮ単結晶の成長方法に用いられるＡｌyＧａ1-yＮ種結晶４について、Ｘ線回折のロッキングカーブにおける回折ピークの半値幅は、１５０ａｒｃｓｅｃ以下が好ましく、５０ａｒｃｓｅｃ以下がより好ましい。また、ＡｌyＧａ1-yＮ種結晶４の転位密度は、１×１０6ｃｍ-2以下が好ましい。ここで、結晶の転位密度の測定方法には、特に制限はなく、たとえば結晶の表面をエッチングすることにより得られるピットの密度（ＥＰＤ；エッチピット密度）を測定することができる。Ｘ線回折のロッキングカーブにおける回折ピークの半値幅が１５０ａｒｃｓｅｃ以下または転位密度が１×１０6ｃｍ-2以下の高品質のＡｌyＧａ1-yＮ種結晶の主表面上には、高品質のＡｌxＧａ1-xＮ単結晶を成長させることができる。 In addition, regarding the Al y Ga 1-y N seed crystal 4 used in the Al x Ga 1-x N single crystal growth method of the present embodiment, the half width of the diffraction peak in the rocking curve of X-ray diffraction is 150 arcsec or less. Preferably, it is 50 arcsec or less. Further, the dislocation density of the Al y Ga 1-y N seed crystal 4 is preferably 1 × 10 6 cm −2 or less. Here, the method for measuring the dislocation density of the crystal is not particularly limited, and for example, the density of pits (EPD; etch pit density) obtained by etching the surface of the crystal can be measured. On the main surface of a high-quality Al y Ga 1-y N seed crystal having a half-width of a diffraction peak in an X-ray diffraction rocking curve of 150 arcsec or less or a dislocation density of 1 × 10 6 cm −2 or less, An Al x Ga 1-x N single crystal can be grown.
  （実施例１）
  １．ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）の成長
  図３を参照して、ＷＣ製の坩堝本体１２ｑの下部に、原料としてＡｌＮ粉末（ＡｌsＧａ1-sＮ原料２）およびＳｉ粉末（ＩＶＢ族元素）を配置した。ここで、原料中におけるＳｉ粉末（ＩＶＢ族元素）の含有率は、３００ｐｐｍとした。次いで、ＷＣ製の坩堝蓋板１２ｐの内面上に、結晶径が４０ｍｍの下地結晶１としてのＳｉＣ下地結晶をその主表面１ｍである（０００１）Ｓｉ表面が原料に対向するように配置した。 Example 1
1. Growth of AlN seed crystal (Al y Ga 1-y N seed crystal) Referring to FIG. 3, AlN powder (Al s Ga 1-s N raw material 2) and Si are used as raw materials at the bottom of crucible body 12q made of WC. Powder (IVB group element) was placed. Here, the content rate of Si powder (IVB group element) in the raw material was 300 ppm. Next, on the inner surface of the WC crucible lid plate 12p, an SiC base crystal as the base crystal 1 having a crystal diameter of 40 mm was arranged so that the (0001) Si surface, which is the main surface 1 m, faces the raw material.
  次に、図１および図３を参照して、反応容器１１内にＮ2ガスを流しながら、高周波加熱コイル１４を用いて坩堝１２内の温度を上昇させた。坩堝１２内の昇温中は、坩堝１２の坩堝蓋板１２ｐ側の温度をＡｌsＧａ1-sＮ原料２側の温度よりも高くして、昇温中に坩堝蓋板１２ｐの表面をエッチングにより清浄するとともに、昇温中に坩堝１２内部から放出された不純物を、通気口１２ｃを通じて除去した。 Next, referring to FIG. 1 and FIG. 3, the temperature in the crucible 12 was increased using the high-frequency heating coil 14 while flowing N 2 gas into the reaction vessel 11. During the temperature rise in the crucible 12, the temperature on the crucible lid plate 12p side of the crucible 12 is set higher than the temperature on the Al s Ga 1-s N raw material 2 side, and the surface of the crucible lid plate 12p is etched during the temperature rise. In addition, the impurities released from the crucible 12 during the temperature increase were removed through the vent 12c.
  次に、坩堝１２のＡｌsＧａ1-sＮ原料２側の温度（昇華温度）を１７００℃、坩堝蓋板１２ｐ側の温度（結晶成長温度）を１６００℃にして、原料からＡｌＮおよびＳｉを昇華させて、坩堝蓋板１２ｐの内面上に配置されたＳｉＣ下地結晶１の（０００１）Ｓｉ表面（主表面１ｍ）上で、ＡｌＮを再度固化させてＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶４）を成長させた。ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶４）成長中も、反応容器１１内の坩堝１２の外側にＮ2ガスを流し続け、反応容器１１内の坩堝１２の外側のガス分圧が１０１．３ｈＰａ～１０１３ｈＰａ程度になるように、Ｎ2ガス導入量とＮ2ガス排出量とを制御した。上記の結晶成長条件で８０時間ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶４）を成長させた後、室温（２５℃）まで冷却して、坩堝蓋板１２ｐを取り出したところ、ＳｉＣ下地結晶１の（０００１）Ｓｉ表面（主表面１ｍ）上に、結晶径Ｄが４０ｍｍで厚さＴ0が１ｍｍのＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶４）が成長していた。 Next, the Al s Ga 1-s N raw material 2 side temperature (sublimation temperature) of the crucible 12 is 1700 ° C., the crucible lid plate 12p side temperature (crystal growth temperature) is 1600 ° C., and AlN and Si are removed from the raw material. subliming, SiC base crystal 1 (0001) disposed on the inner surface of the crucible cover plate 12p on the Si surface (main surface 1 m), solidifying the AlN again AlN seed crystal (Al y Ga 1-y N A seed crystal 4) was grown. During the growth of the AlN seed crystal (Al y Ga 1-y N seed crystal 4), the N 2 gas continues to flow outside the crucible 12 in the reaction vessel 11, and the gas partial pressure outside the crucible 12 in the reaction vessel 11 is increased. The amount of N 2 gas introduced and the amount of N 2 gas discharged were controlled so as to be about 101.3 hPa to 1013 hPa. After growing an AlN seed crystal (Al y Ga 1-y N seed crystal 4) for 80 hours under the above crystal growth conditions, cooling to room temperature (25 ° C.) and taking out the crucible cover plate 12p, On the (0001) Si surface of crystal 1 (main surface 1 m), an AlN seed crystal (Al y Ga 1-y N seed crystal 4) having a crystal diameter D of 40 mm and a thickness T 0 of 1 mm was grown.
  次に、このＡｌＮ種結晶の主表面に平行な面でスライスして、スライス面を研磨して、結晶径Ｄが４０ｍｍで厚さＴが０．２１ｍｍのＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶４）を得た。このＡｌＮ種結晶におけるＳｉ（ＩＶＢ族元素）の含有率は、ＳＩＭＳ（２次イオン質量分析）により測定したところ、８０ｐｐｍであった。このＡｌＮ種結晶のＸ線回折におけるロッキングカーブを測定したところ、回折ピークの半値幅は１８０ａｒｃｓｅｃであった。 Next, the AlN seed crystal is sliced in a plane parallel to the main surface, and the slice surface is polished to obtain an AlN seed crystal (Al y Ga 1-y) having a crystal diameter D of 40 mm and a thickness T of 0.21 mm. N seed crystal 4) was obtained. The Si (IVB group element) content in the AlN seed crystal was 80 ppm as measured by SIMS (secondary ion mass spectrometry). When the rocking curve in X-ray diffraction of this AlN seed crystal was measured, the half-width of the diffraction peak was 180 arcsec.
  ２．ＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶）の成長
  図１を参照して、ＷＣ製の坩堝本体１２ｑの下部に、原料としてＡｌＮ粉末（ＡｌtＧａ1-tＮ原料３）を配置した。次いで、ＷＣ製の坩堝蓋板１２ｐの内面上に、結晶径Ｄが４０ｍｍで厚さＴが０．２１ｍｍのＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶４）をその主表面４ｍである（０００１）Ａｌ表面がＡｌＮ粉末（ＡｌtＧａ1-tＮ原料３）に対向するように配置した。 2. Growth of AlN single crystal (Al x Ga 1-x N single crystal) Referring to FIG. 1, AlN powder (Al t Ga 1-t N raw material 3) is disposed as a raw material at the bottom of a WC crucible body 12q. did. Next, an AlN seed crystal (Al y Ga 1-y N seed crystal 4) having a crystal diameter D of 40 mm and a thickness T of 0.21 mm on the inner surface of the WC crucible lid plate 12p is 4 m on the main surface. (0001) Al surface was arranged to face the AlN powder (Al t Ga 1-t N raw material 3).
  次に、反応容器１１内にＮ2ガスを流しながら、高周波加熱コイル１４を用いて坩堝１２内の温度を上昇させた。坩堝１２内の昇温中は、坩堝１２の坩堝蓋板１２ｐ側の温度をＡｌtＧａ1-tＮ原料３側の温度よりも高くして、昇温中に坩堝蓋板１２ｐおよびＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶４）の表面をエッチングにより清浄するとともに、昇温中に坩堝１２内部から放出された不純物を、通気口１２ｃを通じて除去した。 Next, the temperature in the crucible 12 was raised using the high frequency heating coil 14 while flowing N 2 gas into the reaction vessel 11. Noboru Yutakachu in the crucible 12, the temperature of the crucible cover plate 12p side of the crucible 12 to be higher than the temperature of the Al t Ga 1-t N raw material 3 side, crucible cover plate 12p and AlN seed in warm crystal The surface of (Al y Ga 1-y N seed crystal 4) was cleaned by etching, and impurities released from the crucible 12 during the temperature increase were removed through the vent 12c.
  次に、坩堝１２のＡｌtＧａ1-tＮ原料３側の温度（昇華温度）を１９００℃、ＡｌyＧａ1-yＮ種結晶４側の温度（結晶成長温度）を１８００℃にして、原料からＡｌＮを昇華させて、坩堝１２の上部のＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶４）上で、ＡｌＮを再度固化させてＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶５）を成長させた。ＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶５）成長中も、反応容器１１内の坩堝１２の外側にＮ2ガスを流し続け、反応容器１１内の坩堝１２の外側のガス分圧が１０１．３ｈＰａ～１０１３ｈＰａ程度になるように、Ｎ2ガス導入量とＮ2ガス排出量とを制御した。上記の結晶成長条件で３０時間ＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶５）を成長させた後、室温（２５℃）まで冷却して、坩堝蓋板１２ｐを取り出したところ、ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶４）の主表面４ｍ上にＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶５）が成長していた。 Next, the temperature (sublimation temperature) on the Al t Ga 1-t N raw material 3 side of the crucible 12 is 1900 ° C., the temperature (crystal growth temperature) on the Al y Ga 1-y N seed crystal 4 side is 1800 ° C., AlN is sublimated from the raw material, and AlN is solidified again on the AlN seed crystal (Al y Ga 1-y N seed crystal 4) at the top of the crucible 12 to obtain an AlN single crystal (Al x Ga 1-x N single crystal). 5) was grown. Even during the growth of the AlN single crystal (Al x Ga 1-x N single crystal 5), the N 2 gas continues to flow outside the crucible 12 in the reaction vessel 11, and the gas partial pressure outside the crucible 12 in the reaction vessel 11 is reduced. The amount of N 2 gas introduced and the amount of N 2 gas discharged were controlled so as to be about 101.3 hPa to 1013 hPa. After growing an AlN single crystal (Al x Ga 1-x N single crystal 5) for 30 hours under the above-mentioned crystal growth conditions, cooling to room temperature (25 ° C.) and taking out the crucible lid plate 12p, An AlN single crystal (Al x Ga 1-x N single crystal 5) was grown on the main surface 4m of the crystal (Al y Ga 1-y N seed crystal 4).
  このＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶５）の大きさは、結晶径が４０ｍｍで厚さが４ｍｍであった。このＡｌＮ単結晶のＸ線回折におけるロッキングカーブを測定したところ、回折ピークの半値幅は２２０ａｒｃｓｅｃと小さかった。また、このＡｌＮ単結晶の転位密度は、ＥＰＤ（エッチピット密度）測定により算出したところ、５×１０6ｃｍ-2と低くかった。すなわち、実施例１のＡｌＮ単結晶は高品質であった。結果を表１にまとめた。 The AlN single crystal (Al x Ga 1-x N single crystal 5) had a crystal diameter of 40 mm and a thickness of 4 mm. When the rocking curve in X-ray diffraction of this AlN single crystal was measured, the half width of the diffraction peak was as small as 220 arcsec. The dislocation density of the AlN single crystal was as low as 5 × 10 6 cm −2 as calculated by EPD (etch pit density) measurement. That is, the AlN single crystal of Example 1 was high quality. The results are summarized in Table 1.
  （実施例２）
  １．ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）の成長
  実施例１と同様にして、結晶径Ｄが４０ｍｍで厚さＴ0が１ｍｍのＡｌＮ種結晶を成長させた。このＡｌＮ種結晶をその主表面と平行な面でスライスして、そのスライス面を研磨して結晶径Ｄが４０ｍｍで厚さＴが０．２４ｍｍのＡｌＮ種結晶を得た。このＡｌＮ種結晶におけるＳｉ（ＩＶＢ族元素）の含有率は８０ｐｐｍであった。また、このＡｌＮ種結晶のＸ線回折のロッキングカーブ測定における回折ピークの半値幅は１８０ａｒｃｓｅｃであった。 (Example 2)
1. Growth of AlN seed crystal (Al y Ga 1-y N seed crystal) In the same manner as in Example 1, an AlN seed crystal having a crystal diameter D of 40 mm and a thickness T 0 of 1 mm was grown. The AlN seed crystal was sliced along a plane parallel to the main surface, and the sliced surface was polished to obtain an AlN seed crystal having a crystal diameter D of 40 mm and a thickness T of 0.24 mm. The Si (IVB group element) content in the AlN seed crystal was 80 ppm. Further, the half width of the diffraction peak in the rocking curve measurement of the X-ray diffraction of this AlN seed crystal was 180 arcsec.
  ２．ＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶）の成長
  次に、上記結晶径Ｄが４０ｍｍで厚さＴが０．２４ｍｍのＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）を用いたこと以外は、実施例１と同様にして、ＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶５）を成長させた。得られたＡｌＮ単結晶の大きさは、結晶径が４０ｍｍで厚さが４ｍｍであった。このＡｌＮ単結晶のＸ線回折のロッキングカーブ測定における回折ピークの半値幅は２３０ａｒｃｓｅｃと小さかった。また、このＡｌＮ単結晶の転位密度は、６×１０6ｃｍ-2と低かった。すなわち、実施例２のＡｌＮ単結晶は高品質であった。結果を表１にまとめた。 2. Use AlN growth then the single crystal (Al x Ga 1-x N single crystal), the crystal diameter D is the thickness T at 40 mm AlN seed crystal of 0.24mm the (Al y Ga 1-y N seed crystal) An AlN single crystal (Al x Ga 1-x N single crystal 5) was grown in the same manner as in Example 1 except that. The obtained AlN single crystal had a crystal diameter of 40 mm and a thickness of 4 mm. The half-width of the diffraction peak in the X-ray diffraction rocking curve measurement of this AlN single crystal was as small as 230 arcsec. The dislocation density of the AlN single crystal was as low as 6 × 10 6 cm −2 . That is, the AlN single crystal of Example 2 was high quality. The results are summarized in Table 1.
  （比較例１）
  １．ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）の成長
  結晶径が２０ｍｍのＳｉＣ下地結晶を用いたこと以外は、実施例１と同様にして、結晶径Ｄが２０ｍｍで厚さＴ0が１ｍｍのＡｌＮ種結晶を成長させた。このＡｌＮ種結晶をその主表面と平行な面でスライスして、そのスライス面を研磨して結晶径Ｄが２０ｍｍで厚さＴが０．２５ｍｍのＡｌＮ種結晶を得た。このＡｌＮ種結晶におけるＳｉ（ＩＶＢ族元素）の含有率は８０ｐｐｍであった。また、このＡｌＮ種結晶のＸ線回折のロッキングカーブ測定における回折ピークの半値幅は１６０ａｒｃｓｅｃであった。 (Comparative Example 1)
1. Growth of AlN seed crystal (Al y Ga 1-y N seed crystal) The crystal diameter D was 20 mm and the thickness T 0 was the same as in Example 1 except that a SiC base crystal having a crystal diameter of 20 mm was used. A 1 mm AlN seed crystal was grown. The AlN seed crystal was sliced along a plane parallel to the main surface, and the sliced surface was polished to obtain an AlN seed crystal having a crystal diameter D of 20 mm and a thickness T of 0.25 mm. The Si (IVB group element) content in the AlN seed crystal was 80 ppm. Further, the half width of the diffraction peak in the rocking curve measurement of the X-ray diffraction of this AlN seed crystal was 160 arcsec.
  ２．ＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶）の成長
  次に、上記の結晶径Ｄが２０ｍｍで厚さＴが０．２５ｍｍのＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）を用いたこと以外は、実施例１と同様にして、ＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶５）を成長させた。得られたＡｌＮ単結晶の大きさは、結晶径が２０ｍｍで厚さが４ｍｍであった。このＡｌＮ単結晶のＸ線回折のロッキングカーブ測定における回折ピークの半値幅は３５０ａｒｃｓｅｃと大きかった。また、このＡｌＮ単結晶の転位密度は、５×１０7ｃｍ-2と高かった。すなわち、実施例２のＡｌＮ単結晶は低品質であった。結果を表１にまとめた。 2. Growth of AlN Single Crystal (Al x Ga 1-x N Single Crystal) Next, an AlN seed crystal (Al y Ga 1-y N seed crystal) having the crystal diameter D of 20 mm and a thickness T of 0.25 mm is prepared. An AlN single crystal (Al x Ga 1-x N single crystal 5) was grown in the same manner as in Example 1 except that it was used. The obtained AlN single crystal had a crystal diameter of 20 mm and a thickness of 4 mm. The half-width of the diffraction peak in the X-ray diffraction rocking curve measurement of this AlN single crystal was as large as 350 arcsec. The dislocation density of this AlN single crystal was as high as 5 × 10 7 cm −2 . That is, the AlN single crystal of Example 2 was low quality. The results are summarized in Table 1.
  （比較例２）
  １．ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）の成長
  原料としてＡｌＮ粉末（ＡｌsＧａ1-sＮ原料２）のみを用いたこと以外は、実施例１と同様にして、結晶径Ｄが４０ｍｍで厚さＴ0が１ｍｍのＡｌＮ種結晶を成長させた。このＡｌＮ種結晶をその主表面と平行な面でスライスして、そのスライス面を研磨して結晶径Ｄが４０ｍｍで厚さＴが０．３２ｍｍのＡｌＮ種結晶を得た。また、このＡｌＮ種結晶のＸ線回折のロッキングカーブ測定における回折ピークの半値幅は２８０ａｒｃｓｅｃと大きかった。 (Comparative Example 2)
1. Growth of AlN seed crystal (Al y Ga 1-y N seed crystal) Crystal diameter D in the same manner as in Example 1 except that only AlN powder (Al s Ga 1-s N raw material 2) was used as a raw material. An AlN seed crystal having a thickness of 40 mm and a thickness T 0 of 1 mm was grown. The AlN seed crystal was sliced along a plane parallel to the main surface, and the sliced surface was polished to obtain an AlN seed crystal having a crystal diameter D of 40 mm and a thickness T of 0.32 mm. Further, the half width of the diffraction peak in the X-ray diffraction rocking curve measurement of the AlN seed crystal was as large as 280 arcsec.
  ２．ＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶）の成長
  次に、上記の結晶径Ｄが４０ｍｍで厚さＴが０．３２ｍｍのＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）を用いたこと以外は、実施例１と同様にして、ＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶５）を成長させた。得られたＡｌＮ単結晶の大きさは、結晶径が４０ｍｍで厚さが４ｍｍであった。このＡｌＮ単結晶のＸ線回折のロッキングカーブ測定における回折ピークの半値幅は４６０ａｒｃｓｅｃと大きかった。また、このＡｌＮ単結晶の転位密度は、１×１０8ｃｍ-2と高かった。すなわち、比較例２のＡｌＮ単結晶は低品質であった。結果を表１にまとめた。 2. Growth of AlN Single Crystal (Al x Ga 1-x N Single Crystal) Next, an AlN seed crystal (Al y Ga 1-y N seed crystal) having the crystal diameter D of 40 mm and a thickness T of 0.32 mm is prepared. An AlN single crystal (Al x Ga 1-x N single crystal 5) was grown in the same manner as in Example 1 except that it was used. The obtained AlN single crystal had a crystal diameter of 40 mm and a thickness of 4 mm. The half width of the diffraction peak in the X-ray diffraction rocking curve measurement of this AlN single crystal was as large as 460 arcsec. The dislocation density of the AlN single crystal was as high as 1 × 10 8 cm −2 . That is, the AlN single crystal of Comparative Example 2 was low quality. The results are summarized in Table 1.
  （実施例３）
  １．ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）の成長
  図２を参照して、ＷＣ製の坩堝本体１２ｑの下部に、原料としてＡｌＮ粉末（ＡｌsＧａ1-sＮ原料２）およびＳｉ粉末（ＩＶＢ族元素）を配置した。ここで、原料中におけるＳｉ粉末（ＩＶＢ族元素）の含有率は、５００ｐｐｍとした。次いで、原料に対向するようにＷＣ製の坩堝蓋板１２ｐを配置した。 (Example 3)
1. Growth of AlN seed crystal (Al y Ga 1-y N seed crystal) Referring to FIG. 2, AlN powder (Al s Ga 1-s N raw material 2) and Si are used as raw materials at the bottom of crucible body 12q made of WC. Powder (IVB group element) was placed. Here, the content rate of Si powder (IVB group element) in the raw material was 500 ppm. Next, a crucible lid plate 12p made of WC was disposed so as to face the raw material.
  次に、図１および図２を参照して、反応容器１１内にＮ2ガスを流しながら、高周波加熱コイル１４を用いて坩堝１２内の温度を上昇させた。坩堝１２内の昇温中は、坩堝１２の坩堝蓋板１２ｐ側の温度をＡｌsＧａ1-sＮ原料２側の温度よりも高くして、昇温中に坩堝蓋板１２ｐの表面をエッチングにより清浄するとともに、昇温中に坩堝１２内部から放出された不純物を、通気口１２ｃを通じて除去した。 Next, referring to FIG. 1 and FIG. 2, the temperature in the crucible 12 was raised using the high-frequency heating coil 14 while flowing N 2 gas into the reaction vessel 11. During the temperature rise in the crucible 12, the temperature on the crucible lid plate 12p side of the crucible 12 is set higher than the temperature on the Al s Ga 1-s N raw material 2 side, and the surface of the crucible lid plate 12p is etched during the temperature rise. In addition, the impurities released from the crucible 12 during the temperature increase were removed through the vent 12c.
  次に、坩堝１２のＡｌsＧａ1-sＮ原料２側の温度（昇華温度）を２２００℃、坩堝蓋板１２ｐ側の温度（結晶成長温度）を２１５０℃にして、原料からＡｌＮおよびＳｉを昇華させて、坩堝１２の上部の坩堝蓋板１２ｐ上で、ＡｌＮを再度固化させてＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶４）を成長させた。ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶４）成長中も、反応容器１１内の坩堝１２の外側にＮ2ガスを流し続け、反応容器１１内の坩堝１２の外側のガス分圧が１０１．３ｈＰａ～１０１３ｈＰａ程度になるように、Ｎ2ガス導入量とＮ2ガス排出量とを制御した。上記の結晶成長条件で１５時間ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶４）を成長させた後、室温（２５℃）まで冷却して、坩堝蓋板１２ｐを取り出したところ、坩堝蓋板１２ｐの内面上に六角平板状の複数個のＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶４）が成長していた。 Next, the temperature (sublimation temperature) on the Al s Ga 1-s N raw material 2 side of the crucible 12 is 2200 ° C., the temperature (crystal growth temperature) on the crucible lid 12p side is 2150 ° C., and AlN and Si are removed from the raw material. sublimating, on top of the crucible cover plate 12p of the crucible 12, it was grown AlN was solidified again AlN seed crystal (Al y Ga 1-y N seed crystal 4). During the growth of the AlN seed crystal (Al y Ga 1-y N seed crystal 4), the N 2 gas continues to flow outside the crucible 12 in the reaction vessel 11, and the gas partial pressure outside the crucible 12 in the reaction vessel 11 is increased. The amount of N 2 gas introduced and the amount of N 2 gas discharged were controlled so as to be about 101.3 hPa to 1013 hPa. After growing an AlN seed crystal (Al y Ga 1-y N seed crystal 4) for 15 hours under the above crystal growth conditions, cooling to room temperature (25 ° C.) and taking out the crucible lid plate 12p, A plurality of hexagonal flat plate-like AlN seed crystals (Al y Ga 1-y N seed crystals 4) were grown on the inner surface of the plate 12p.
  上記複数個のＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶４）のうちの１個のＡｌＮ種結晶の大きさは、結晶径Ｄが２５ｍｍ、厚さＴが０．１６ｍｍであった。このＡｌＮ種結晶におけるＳｉ（ＩＶＢ族元素）の含有率は、１５０ｐｐｍであった。このＡｌＮ種結晶のＸ線回折のロッキングカーブ測定における回折ピークの半値幅は７０ａｒｃｓｅｃとたいへん小さかった。すなわち、実施例３のＡｌＮ種結晶はたいへん高品質であった。 Among the plurality of AlN seed crystals (Al y Ga 1-y N seed crystal 4), one AlN seed crystal had a crystal diameter D of 25 mm and a thickness T of 0.16 mm. The Si (IVB group element) content in the AlN seed crystal was 150 ppm. The full width at half maximum of the diffraction peak in the X-ray diffraction rocking curve measurement of the AlN seed crystal was as small as 70 arcsec. That is, the AlN seed crystal of Example 3 was very high quality.
  ２．ＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶）の成長
  次に、上記の結晶径Ｄが２５ｍｍで厚さＴが０．１６ｍｍのＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）を用いたこと以外は、実施例１と同様にして、ＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶５）を成長させた。得られたＡｌＮ単結晶の大きさは、結晶径が２５ｍｍで厚さが４ｍｍであった。このＡｌＮ単結晶のＸ線回折のロッキングカーブ測定における回折ピークの半値幅は７０ａｒｃｓｅｃとたいへん小さかった。また、このＡｌＮ単結晶の転位密度は、６×１０5ｃｍ-2とたいへん低かった。すなわち、実施例３のＡｌＮ単結晶はたいへん高品質であった。結果を表１にまとめた。 2. Growth of AlN Single Crystal (Al x Ga 1-x N Single Crystal) Next, an AlN seed crystal (Al y Ga 1-y N seed crystal) having the crystal diameter D of 25 mm and a thickness T of 0.16 mm is prepared. An AlN single crystal (Al x Ga 1-x N single crystal 5) was grown in the same manner as in Example 1 except that it was used. The obtained AlN single crystal had a crystal diameter of 25 mm and a thickness of 4 mm. The half width of the diffraction peak in the X-ray diffraction rocking curve measurement of this AlN single crystal was very small at 70 arcsec. Further, the dislocation density of the AlN single crystal was as low as 6 × 10 5 cm −2 . That is, the AlN single crystal of Example 3 was very high quality. The results are summarized in Table 1.
  （実施例４）
  １．ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）の成長
  ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）の成長時間を１０時間としたこと以外は、実施例３と同様にして、複数のＡｌＮ種結晶を成長させた。これらのＡｌＮ種結晶のうちの１個のＡｌＮ種結晶の大きさは、結晶径Ｄが１４ｍｍ、厚さＴが０．１８ｍｍであった。このＡｌＮ種結晶におけるＳｉ（ＩＶＢ族元素）の含有率は、１２０ｐｐｍであった。このＡｌＮ種結晶のＸ線回折のロッキングカーブ測定における回折ピークの半値幅は８０ａｒｃｓｅｃとたいへん小さかった。すなわち、実施例４のＡｌＮ種結晶はたいへん高品質であった。 Example 4
1. Except that AlN seed crystal (Al y Ga 1-y N seed crystal) growth AlN seed crystal (Al y Ga 1-y N seed crystal) growth time was 10 hours, in the same manner as in Example 3, A plurality of AlN seed crystals were grown. Of these AlN seed crystals, one AlN seed crystal had a crystal diameter D of 14 mm and a thickness T of 0.18 mm. The Si (IVB group element) content in the AlN seed crystal was 120 ppm. The half-width of the diffraction peak in the X-ray diffraction rocking curve measurement of this AlN seed crystal was very small at 80 arcsec. That is, the AlN seed crystal of Example 4 was very high quality.
  ２．ＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶）の成長
  次に、上記の結晶径Ｄが１４ｍｍで厚さＴが０．１８ｍｍのＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）を用いたこと以外は、実施例１と同様にして、ＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶５）を成長させた。得られたＡｌＮ単結晶の大きさは、結晶径が１４ｍｍで厚さが４ｍｍであった。このＡｌＮ単結晶のＸ線回折のロッキングカーブ測定における回折ピークの半値幅は８０ａｒｃｓｅｃとたいへん小さかった。また、このＡｌＮ単結晶の転位密度は、８×１０5ｃｍ-2とたいへん低かった。すなわち、実施例３のＡｌＮ単結晶はたいへん高品質であった。結果を表１にまとめた。 2. Growth of AlN single crystal (Al x Ga 1-x N single crystal) Next, an AlN seed crystal (Al y Ga 1-y N seed crystal) having a crystal diameter D of 14 mm and a thickness T of 0.18 mm is prepared. An AlN single crystal (Al x Ga 1-x N single crystal 5) was grown in the same manner as in Example 1 except that it was used. The obtained AlN single crystal had a crystal diameter of 14 mm and a thickness of 4 mm. The half width of the diffraction peak in the X-ray diffraction rocking curve measurement of this AlN single crystal was as small as 80 arcsec. Further, the dislocation density of the AlN single crystal was as low as 8 × 10 5 cm −2 . That is, the AlN single crystal of Example 3 was very high quality. The results are summarized in Table 1.
  （実施例５）
  １．ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）の成長
  原料中のＩＶＢ族元素として含有率４００ｐｐｍのＣ（炭素）粉末を用いて、ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）の成長時間を２０時間としたこと以外は、実施例３と同様にして、複数のＡｌＮ種結晶を成長させた。これらのＡｌＮ種結晶のうちの１個のＡｌＮ種結晶の大きさは、結晶径Ｄが２２ｍｍ、厚さＴが０．１４ｍｍであった。このＡｌＮ種結晶におけるＣ（ＩＶＢ族元素）の含有率は、ＳＩＭＳ（２次イオン質量分析）により測定したところ、１２０ｐｐｍであった。このＡｌＮ種結晶のＸ線回折のロッキングカーブ測定における回折ピークの半値幅は２５ａｒｃｓｅｃと極めて小さかった。すなわち、実施例５のＡｌＮ種結晶は極めて高品質であった。 (Example 5)
1. With C (carbon) powder content 400ppm as Group IVB element of growing raw material AlN seed crystal (Al y Ga 1-y N seed crystal), AlN seed crystal (Al y Ga 1-y N seed crystal) A plurality of AlN seed crystals were grown in the same manner as in Example 3 except that the growth time was set to 20 hours. Among these AlN seed crystals, one AlN seed crystal had a crystal diameter D of 22 mm and a thickness T of 0.14 mm. The content of C (IVB group element) in this AlN seed crystal was 120 ppm as measured by SIMS (secondary ion mass spectrometry). The half-width of the diffraction peak in the X-ray diffraction rocking curve measurement of the AlN seed crystal was as extremely small as 25 arcsec. That is, the AlN seed crystal of Example 5 was extremely high quality.
  ２．ＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶）の成長
  次に、上記の結晶径Ｄが２２ｍｍで厚さＴが０．１４ｍｍのＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）を用いたこと以外は、実施例１と同様にして、ＡｌＮ単結晶（ＡｌxＧａ1-x
Ｎ単結晶５）を成長させた。得られたＡｌＮ単結晶の大きさは、結晶径が２２ｍｍで厚さが４ｍｍであった。このＡｌＮ単結晶のＸ線回折のロッキングカーブ測定における回折ピークの半値幅は２０ａｒｃｓｅｃと極めて小さかった。また、このＡｌＮ単結晶の転位密度は、５×１０4ｃｍ-2と極めて低かった。すなわち、実施例５のＡｌＮ単結晶は極めて高品質であった。結果を表１にまとめた。 2. Growth of AlN Single Crystal (Al x Ga 1-x N Single Crystal) Next, an AlN seed crystal (Al y Ga 1-y N seed crystal) having the crystal diameter D of 22 mm and a thickness T of 0.14 mm is prepared. An AlN single crystal (Al x Ga 1 -x) was used in the same manner as in Example 1 except that it was used.
N single crystals 5) were grown. The obtained AlN single crystal had a crystal diameter of 22 mm and a thickness of 4 mm. The half width of the diffraction peak in the X-ray diffraction rocking curve measurement of the AlN single crystal was as extremely small as 20 arcsec. Further, the dislocation density of this AlN single crystal was as extremely low as 5 × 10 4 cm −2 . That is, the AlN single crystal of Example 5 was extremely high quality. The results are summarized in Table 1.
  （実施例６）
  １．ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）の成長
  原料中のＩＶＢ族元素として含有率６００ｐｐｍのＣ粉末を用いて、ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）の成長時間を４０時間としたこと以外は、実施例３と同様にして、複数のＡｌＮ種結晶を成長させた。これらのＡｌＮ種結晶のうちの１個のＡｌＮ種結晶の大きさは、結晶径Ｄが４０ｍｍ、厚さＴが０．１７ｍｍであった。このＡｌＮ種結晶におけるＣ（ＩＶＢ族元素）の含有率は、１４０ｐｐｍであった。このＡｌＮ種結晶のＸ線回折のロッキングカーブ測定における回折ピークの半値幅は２０ａｒｃｓｅｃと極めて小さかった。すなわち、実施例５のＡｌＮ種結晶は極めて高品質であった。 (Example 6)
1. With C powder content 600ppm as Group IVB element of growing raw material AlN seed crystal (Al y Ga 1-y N seed crystal), AlN seed crystal (Al y Ga 1-y N seed crystal) growth time A plurality of AlN seed crystals were grown in the same manner as in Example 3 except that the time was 40 hours. Of these AlN seed crystals, one AlN seed crystal had a crystal diameter D of 40 mm and a thickness T of 0.17 mm. The content of C (IVB group element) in this AlN seed crystal was 140 ppm. The half-width of the diffraction peak in the X-ray diffraction rocking curve measurement of the AlN seed crystal was as extremely small as 20 arcsec. That is, the AlN seed crystal of Example 5 was extremely high quality.
  ２．ＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶）の成長
  次に、上記の結晶径Ｄが４０ｍｍで厚さＴが０．１７ｍｍのＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）を用いたこと以外は、実施例１と同様にして、ＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶）を成長させた。得られたＡｌＮ単結晶の大きさは、結晶径が４０ｍｍで厚さが４ｍｍであった。このＡｌＮ単結晶のＸ線回折のロッキングカーブ測定における回折ピークの半値幅は１５ａｒｃｓｅｃと極めて小さかった。また、このＡｌＮ単結晶の転位密度は、９×１０3ｃｍ-2と極めて低かった。すなわち、実施例６のＡｌＮ単結晶は極めて高品質であった。結果を表１にまとめた。 2. Growth of AlN single crystal (Al x Ga 1-x N single crystal) Next, an AlN seed crystal (Al y Ga 1-y N seed crystal) having the crystal diameter D of 40 mm and a thickness T of 0.17 mm is prepared. An AlN single crystal (Al x Ga 1-x N single crystal) was grown in the same manner as in Example 1 except that it was used. The obtained AlN single crystal had a crystal diameter of 40 mm and a thickness of 4 mm. The half-width of the diffraction peak in the X-ray diffraction rocking curve measurement of the AlN single crystal was as extremely small as 15 arcsec. Further, the dislocation density of this AlN single crystal was as extremely low as 9 × 10 3 cm −2 . That is, the AlN single crystal of Example 6 was extremely high quality. The results are summarized in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
  また、上記の表１の実施例１～実施例６ならびに比較例１および２におけるＡｌＮ種結晶の結晶径Ｄ（ｍｍ）と厚さＴ（ｍｍ）との関係を、それぞれＥ１～Ｅ６ならびにＣ１およびＣ２として、図４にプロットした。 In addition, the relationship between the crystal diameter D (mm) and the thickness T (mm) of the AlN seed crystal in Examples 1 to 6 and Comparative Examples 1 and 2 in Table 1 above is shown by E1 to E6, C1 and C2 is plotted in FIG.
  表１および図４を参照して、ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）の結晶径Ｄ（ｍｍ）と厚さＴ（ｍｍ）とがＴ≧０．００３Ｄ＋０．１５の関係にある比較例１（Ｃ１）および比較例２（Ｃ２）に比べて、ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）の結晶径Ｄ（ｍｍ）と厚さＴ（ｍｍ）とがＴ＜０．００３Ｄ＋０．１５の関係を満たす実施例１（Ｅ１）～実施例６（Ｅ６）では、Ｘ線回折のロッキングカーブ測定における回折ピークの半値幅が小さく、転位密度が低い高品質のＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶）が得られた。 Referring to Table 1 and FIG. 4, the relationship between the crystal diameter D (mm) and the thickness T (mm) of the AlN seed crystal (Al y Ga 1-y N seed crystal) is T ≧ 0.003D + 0.15. Compared to certain Comparative Example 1 (C1) and Comparative Example 2 (C2), the crystal diameter D (mm) and thickness T (mm) of the AlN seed crystal (Al y Ga 1-y N seed crystal) are T < In Example 1 (E1) to Example 6 (E6) satisfying the relationship of 0.003D + 0.15, a high-quality AlN single crystal having a small half-value width of a diffraction peak in rocking curve measurement of X-ray diffraction and a low dislocation density (Al x Ga 1-x N single crystal) was obtained.
  また、ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）の結晶径Ｄ（ｍｍ）と厚さＴ（ｍｍ）とが０．００２Ｄ＋０．１≦Ｔ＜０．００３Ｄ＋０．１５の関係を満たす実施例１（Ｅ１）～実施例（Ｅ４）に比べて、ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）の結晶径Ｄ（ｍｍ）と厚さＴ（ｍｍ）とがＴ＜０．００２Ｄ＋０．１の関係を満たす実施例５（Ｅ５）および実施例６（Ｅ６）では、Ｘ線回折のロッキングカーブ測定における回折ピークの半値幅がより小さく、転位密度がより低い、さらに高品質のＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶）が得られた。 In addition, the crystal diameter D (mm) and the thickness T (mm) of the AlN seed crystal (Al y Ga 1-y N seed crystal) satisfy the relationship of 0.002D + 0.1 ≦ T <0.003D + 0.15. example 1 (E1) as compared to ~ example (E4), AlN seed crystal (Al y Ga 1-y N seed crystal) crystal diameter D (mm) and thickness T (mm) and the T of <0.002D + 0 In Example 5 (E5) and Example 6 (E6) satisfying the relationship of .1, a high-quality AlN single crystal having a smaller half-value width of a diffraction peak in a rocking curve measurement of X-ray diffraction and a lower dislocation density is obtained. A crystal (Al x Ga 1-x N single crystal) was obtained.
  また、ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）の結晶径Ｄ（ｍｍ）と厚さＴ（ｍｍ）とが０．００２Ｄ＋０．１≦Ｔ＜０．００３Ｄ＋０．１５の関係を満たす実施例１（Ｅ１）～実施例（Ｅ４）において、ＳｉＣ下地結晶（下地結晶）上で成長させたＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）を用いた実施例１（Ｅ１）および実施例２（Ｅ２）に比べて、ＡｌＮ種結晶（ＡｌyＧａ1-yＮ種結晶）結晶核を生成させてその結晶核を成長させたＡｌＮ種結晶を用いた実施例３（Ｅ３）および実施例４（Ｅ４）では、Ｘ線回折のロッキングカーブ測定における回折ピークの半値幅がより小さく、転位密度がより低い、より高品質のＡｌＮ単結晶（ＡｌxＧａ1-xＮ単結晶）が得られた。 In addition, the crystal diameter D (mm) and the thickness T (mm) of the AlN seed crystal (Al y Ga 1-y N seed crystal) satisfy the relationship of 0.002D + 0.1 ≦ T <0.003D + 0.15. In Example 1 (E1) to Example (E4), Example 1 (E1) and implementation using an AlN seed crystal (Al y Ga 1-y N seed crystal) grown on a SiC base crystal (base crystal) Compared to Example 2 (E2), Example 3 (E3) and implementation using an AlN seed crystal in which an AlN seed crystal (Al y Ga 1-y N seed crystal) crystal nucleus was generated and grown. In Example 4 (E4), a higher quality AlN single crystal (Al x Ga 1-x N single crystal) having a smaller half-width of the diffraction peak and lower dislocation density in the rocking curve measurement of X-ray diffraction was obtained. It was.
  なお、上記の実施例および比較例は、ＡｌＮ種結晶およびＡｌＮ単結晶について説明したが、ＡｌyＧａ1-yＮ（０＜ｙ≦１）種結晶およびＡｌxＧａ1-xＮ（０＜ｘ≦１）単結晶についても、結晶の構成元素としてＡｌが含まれ、本発明にかかる成長方法が適用され得る限り、同様の結果が得られることはいうまでもない。 In Examples and Comparative Examples described above, it has been described AlN seed crystal and the AlN single crystal, Al y Ga 1-y N (0 <y ≦ 1) seed crystal and Al x Ga 1-x N ( 0 < It is needless to say that the same result can be obtained for the single crystal of x ≦ 1) as long as Al is included as a constituent element of the crystal and the growth method according to the present invention can be applied.
  今回開示された実施の形態および実施例はすべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は、上記した説明でなくて特許請求の範囲によって示され、特許請求の範囲と均等の意味および範囲内のすべての変更が含まれることが意図される。 It should be considered that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

Claims (4)

  1.   結晶径Ｄｍｍと厚さＴｍｍとがＴ＜０．００３Ｄ＋０．１５の関係を満たすＡｌyＧａ1-yＮ（０＜ｙ≦１）種結晶を準備する工程と、
      昇華法により、前記ＡｌyＧａ1-yＮ種結晶の主表面上にＡｌxＧａ1-xＮ（０＜ｘ≦１）単結晶を成長させる工程と、を備えるＡｌxＧａ1-xＮ単結晶の成長方法。     Preparing an Al y Ga 1-y N (0 <y ≦ 1) seed crystal in which the crystal diameter Dmm and the thickness Tmm satisfy the relationship of T <0.003D + 0.15;
    By sublimation, said Al y Ga 1-y Al on the main surface of the N seed crystal x Ga 1-x N Al and a step of growing a (0 <x ≦ 1) single crystal, the x Ga 1-x N Single crystal growth method.
  2.   前記ＡｌyＧａ1-yＮ種結晶は、昇華法により前記ＡｌyＧａ1-yＮ種結晶の結晶核を生成させて前記結晶核を成長させたものである請求項１に記載のＡｌxＧａ1-xＮ単結晶の成長方法。 Said Al y Ga 1-y N seed crystal, said by sublimation Al y Ga 1-y N seed crystal of the crystal nuclei by generating according to claim 1 is obtained by growing the crystal nuclei Al x A method for growing a Ga 1-x N single crystal.
  3.   前記ＡｌyＧａ1-yＮ種結晶は、主表面として（０００１）表面を有する請求項１または請求項２に記載のＡｌxＧａ1-xＮ単結晶の成長方法。 It said Al y Ga 1-y N seed crystal growth method of the Al x Ga 1-x N single crystal according to claim 1 or claim 2 having a (0001) surface as a main surface.
  4.   前記ＡｌyＧａ1-yＮ種結晶は、ＩＶＢ族元素のうちの少なくとも１種類の元素を質量比で１０ｐｐｍ以上含有する請求項１から請求項３までのいずれかに記載のＡｌxＧａ1-xＮ単結晶の成長方法。 It said Al y Ga 1-y N seed crystal according to claim 1 containing 10ppm or more at a mass ratio of at least one element selected IVB group elements to claim 3 Al x Ga 1- x N single crystal growth method.
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